Final Report (FR) CONTRACT N° : G4RT-CT-2002-05103 PROJECT N° : GTC 2-2001-53003 ACRONYM : KATnet TITLE : Key Aerodynamic Technologies for Aircraft Performance Improvement PROJECT CO-ORDINATOR : Airbus Deutschland GmbH PARTNERS : Airbus UK Airbus France BAE Systems Alenia Aeronautica DLR FOI ONERA QinetiQ REPORTING PERIOD : FROM 1 September 2002 TO 31 December 2005 PROJECT START DATE : 1 September 2002 DURATION : 40 months Date of issue of this report : March 2006 Project funded by the European Community under the ‘Competitive and Sustainable Growth’ Programme (1998-2002) Prepared with support of
TITLE : Key Aerodynamic Technologies for Aircraft Performance Improvement PROJECT CO-ORDINATOR : Airbus Deutschland GmbH PARTNERS : Airbus UK Airbus France BAE Systems Alenia Aeronautica DLR FOI ONERA QinetiQ REPORTING PERIOD : FROM 1 September 2002 TO 31 December 2005 PROJECT START DATE : 1 September 2002 DURATION : 40 months Date of issue of this report : March 2006
Project funded by the European Community under the ‘Competitive and Sustainable Growth’
Executive Summary KATnet is a Thematic Network on Key Aerodynamic Technologies supporting the ACARE Vision 2020, and in particular it’s Strategic Research Agenda. The project started on 1 Sep 2002 for a period of 3 years and has been extended by 4 months to 31 Dec 2005. The main objective of KATnet was to identify and assess those aerodynamic technologies that are needed to meet the Vision 2020 goals and to be the European focus for these technologies. This was reached by development of a common R&T strategy in the KATnet technology areas and by providing a communication platform via Internet, workshops and a conference on the subject. KATnet is covering the relevant Technology Areas Low Speed Performance (TA1), High Speed Performance (TA2) and Flow Control Technologies (TA3) including the ten EU funded aeronautical projects/platforms EUROLIFT, HELIX, HiAer, EPISTLE, HiReTT, AEROSHAPE, M-DAW, ALTTA, AEROMEMS II and AWIATOR. Other relevant non-EU activities addressed by KATnet are AIRnet, GARTEUR, ERCOFTAC and corresponding national programmes. Networking activities provided by KATnet are R&T Strategy & Exploitation (WP1), KATnet Website & Newsletters (WP2) and KATnet Conference & Workshops (WP3). The work programme of KATnet was determined by its matrix structure, shown in Fig. 1:
Fig. 1 KATnet Project Structure
The final achievements of KATnet include:
• Identification of promising technologies, quantification of their benefits and maturity, and development of roadmaps for their implementation into future aircraft
• Dissemination of KATnet information via the KATnet homepage and newsletters • Providing of a communication platform by organising workshops on key technology
areas and an international conference on the subject. In order to continue the successful networking activities of KATnet concerning the Vision 2020 challenges, a follow-on proposal KATnet II on Key Aerodynamic Technologies has been submitted to the Commission within FP6 being under contract negotiation now.
Overview - P. Thiede o.b.o. A-D In the ACARE Vision for 2020, the Group of Personalities has formulated a clear set of requirements for civil transport aircraft operation in order to reach the following specific goals:
• Five-fold reduction in accidents • Halving perceived aircraft noise • 50% cut in CO2 emissions per passenger-km • 80% cut in NOx emissions • Air traffic system capable of handling 16 million flights a year • 99% of all flights within 15 minutes of timetable
The main objective of KATnet was to support the global strategic approach of the Strategic Research Agenda (SRA) of ACARE. This has been reached by development of a common RTD strategy in the KATnet technology areas and by providing a communication platform for all aircraft disciplines concerned directly or indirectly with aircraft performance improvement. This platform was realised by Internet, workshops and a conference on the subject. KATnet has identified and assessed key aerodynamic technologies that open up to meet the challenges of the Vision 2020 and has investigated relevant implementation strategies. The work programme of KATnet, Fig. 2, is determined by its matrix structure consisting of four Work Packages (WP) and three Technology Areas (TA).
Fig. 2 Work Programme Overview
KATnet is covering the relevant Technology Areas for aircraft performance improvement including the corresponding EU funded projects/ platforms as
• TA2 High Speed Performance: HiReTT, AEROSHAPE, M-DAW
• TA3 Flow Control Technologies: ALTTA, AEROMEMS II, AWIATOR
and relevant non-EU activities as AIRnet, GARTEUR, ERCOFTAC and national programmes. The Work Packages focus on the main networking activities as
• WP0 Project Management
• WP1 R&T Strategy Development & Exploitation Technology Opportunities – Implementation Strategies – Exploitation of Knowledge
• WP2 KATnet Website & Newsletters Website Set-up & Update – Communication Infrastructure – Newsletters • WP3 KATnet Conference & Workshops European Conference – Area Workshops
The KATnet consortium consists of Airbus Deutschland GmbH (Co-ordinator), Airbus UK, Airbus France, BAE Systems, Alenia Aeronautica, DLR, FOI, ONERA and QinetiQ. The project started on 1 Sep 2002 for a period of 3 years and has been extended by 4 months to 31 Dec 2005. The actual project schedule & main milestones are shown in Fig. 3.
The networking activities of KATnet are summarised as follows: WP0 Project Management KATnet was managed on the basis of its project management structure, Fig. 7 of the DoW, and the Consortium Agreement. After counter-signature of the KATnet contract by the EU mid of Nov 2002, the 1 Sep 2002 was confirmed as commencement date of KATnet. During the course of KATnet, three main project meetings, eight Management Board meetings, two Supervisory Board meetings, three workshops on key technology areas, and an international conference were organised, see Fig. 12. The Kick-off meeting was held in conjunction with the first KATnet workshop on High Lift Aerodynamics in Sep 2002 at FOI Stockholm. QinetiQ and FOI committed to the workshop preparation before the KATnet contract was signed. The workshop attracting more than 75 attendees was seen as a promising start of KATnet. On request of the Commission, a KATnet Supervisory Board recruited from senior perso-nalities of the KATnet partner organisations was set up to monitor the networking activities. The first Supervisory Board meeting took place on 5 Sep 2003 just after the second KATnet workshop on High Speed Aerodynamics at the University of Bath, UK. The Midterm Review meeting was performed on 11 March 2004 at QinetiQ Bedford. The progress of the project was assessed with the result to continue with the KATnet activities. The third year of KATnet started with a workshop on Flow Control Technologies and the second Supervisory Board meeting held in Oct 2004 at the University of Poitiers, France. The third KATnet workshop attracted about 130 participants since it was held in conjunction with an AIRnet forum on flow control. The next major KATnet event was the CEAS/KATnet Conference on Key Aerodynamic Technologies held on 20-22 June 2005 in Bremen, Germany. The theme of this conference was to present and discuss aerodynamic technologies that open up to meet the challenges of the Vision 2020. Agreement was reached to amalgamate this conference with the 2005 RAeS Aerodynamics Conference. The conference attracted about 150 attendees including a presence from overseas rating the conference as a top level event. As two KATnet tasks – preparation of the R&T strategy document and compilation of the conference proceedings – could not be completed within the contracted period, the KATnet consortium asked the Commission for an extension of KATnet by four months to 31 Dec 2005 which was accepted. The KATnet Final Review meeting – in conjunction with the third Supervisory Board meeting – took place on 30 Nov 2005 at Airbus D in Bremen. The final KATnet strategy document will be presented there. All KATnet targets have been achieved and no cost problems have been reported during the lifetime of the project. A KATnet follow-on proposal – called KATnet II “Key Aerodynamic Technologies to Meet the Vision 2020 Challenges – has been submitted to the Commission and is under contract negotiation now.
WP1 R&T Strategy Development & Exploitation In WP1 a R&T strategy in the KATnet Technology Areas was under development in co-operation between Airbus UK and the TA’s containing three phases. For that purpose three strategy sub-teams – one for each of the Technology Areas – were formed. The first strategy development phase – identification of those aerodynamic technologies that can deliver against the Vision 2020 goals and scheduled for the first year of KATnet – was delayed by a few months due to the difficulty of quantifying the benefits for some technologies. Technology templates were issued to the members of the TA sub-teams for completion, and a strategy meeting was held. The outcome of this phase was collated in the KATnet Technology Status document, which has been presented at the Midterm Review. In the second phase – aiming on the quantification of the benefits of the main technology opportunities and started at midterm – a strategy framework was derived from the Vision 2020 goals. This framework forming the basis for further more detailed investigations was updated to give also an indication of technology maturity, product benefit, confidence in this benefit and direction of needed investment. Furthermore, a baseline aircraft configuration was agreed for technology evaluation. Status and results of the WP1 strategy development have been presented at the CEAS/KATnet conference. The WP1 activities in the third phase – devoted to the development of implementation strategies for promising technologies into future aircraft – led to the definition of technology development roadmaps. The KATnet Technology Implementation strategy document contains roadmaps for those technologies as laminar flow, turbulent drag reduction, and separation control technologies which the KATnet partners think are promising a step change rather than a small benefit in order to meet the Vision 2020 goals. The final outcome of the KATnet strategy development has been presented at the Final Review meeting, and is described in the KATnet Technology Implementation Strategy report, attachment 1. WP2 KATnet Website & Newsletters The KATnet homepage www.kat-net.com was established and made fully functional in the first year of KATnet under the lead of BAE Systems. A website steering board was set up. A specification document for the KATnet website was prepared and agreed with the partners, and a website design company was contracted for development and programming of the site. The website was structured to allow an easy update and maintenance. In addition to a fully public area – covering information on workshops/conferences and KATnet & member projects, topical new items, and links to other sites – there are three password protected levels for KATnet members, partners, and administrators respectively. Since the website went online in the first year, it was regularly maintained and updated with new data in all areas. The website register of members within the general community was growing steadily with about 250 registered members now. The most useful areas seemed to be the regularly updated information, links to related workshops and conferences, as well as occasional items of news.
Another important communication tool of KATnet were the newsletters. The initial newsletters were compiled as self-containing documents and distributed via the KATnet mailing list. Later the newsletters were edited as part of an integrated newsletter/website concept containing only key information with links to more detailed information on the website. The attempt to create a web-based “European Aerodynamics Research Map” was not very successful because of the weak response of the broader research community. WP3 KATnet Conference & Workshops Three workshops on key technology areas and an international conference have been organised by KATnet. The first KATnet workshop on High Lift Aerodynamics was held on 17-19 Sep 2002 in Stockholm. Its objective was to present and discuss the status and results not only of EU funded high lift projects but also of corresponding GARTEUR and national activities. The workshop attracted more than 75 attendees and was adjudged a success by the workshop reviewer. Workshop proceedings were distributed to all attendees early in 2003. The second KATnet workshop on High Speed Aerodynamics took place on 3-4 Sep 2003 at the University of Bath, UK. This workshop attracted nearly 100 attendees and was adjudged a big success. Copies of all presentations were distributed as CD-ROM to all attendees during December 2003. The third KATnet workshop on Flow Control Technologies was performed on 12-13 Oct 2004 at the University of Poitiers, France. It attracted about 130 participants since it was held in conjunction with an AIRnet forum on flow control. Copies of all presentations were distributed as CD-ROM to all workshop attendees in early 2005. The CEAS/KATnet conference held on 20-22 June 2005 in Bremen, Germany, was devoted to key aerodynamic technologies that open up to meet the challenges of the Vision 2020. Agreement was reached to organise this conference together with DGLR under the auspices of CEAS and to amalgamate it with the 2005 RAeS Aerodynamics Research Conference. The Announcement & Call for Papers was distributed in Feb 2004, and the Programme Committee meeting was held on 18 Nov 2004. The final conference programme contained 23 sessions with 80 papers and posters. The conference was attended by about 150 aircraft engineers and research scientists including a presence from overseas, who adjudged the conference as a world-class event. The conference proceedings were distributed as CD-ROM to all conference participants. Technology Areas (TA1, 2 & 3) The main task of the KATnet Technology Areas was to provide scientific and technological support for planning, preparation and performance of all networking activities and to be a European focus for R&T activities in this area. In the first half of KATnet, the ongoing R&T activities concerning low and high speed aerodynamics as well as flow control technologies in Europe were identified, exploited and in form of technology templates compiled to WP1 for the technology status document. After
midterm, the TA expertise was used to support the strategy development in WP1, in particular the second phase aiming on quantifying the benefits of the key technologies identified in the first phase. Furthermore, TA1 to 3 provided input for the KATnet website and newsletters of WP2 and supported the attempt of WP2 to create a web-based European Aerodynamics Research Map. In addition, the organisation of the three KATnet workshops and the CEAS/KATnet conference concerning participation in programme committees, set-up of meeting programmes, invitation of speakers, chairing of sessions was supported by TA1, 2 & 3. Final Achievements The final project achievements of KATnet are summarised in Fig. 4:
WP1 Strategy & Exploitation – S. Rolston/D. Sawyers, A-UK Objectives for reporting period The objectives of WP1 were to develop a strategy for the future development of aerodynamics technologies and to ensure the exploitation of RTD results from the KATnet family of projects. The strategy development process consisted of three phases
1. Examination of available technology options 2. Identification of those technologies most likely to bring about a step change in aircraft
performance 3. Definition of technology development roadmaps.
Activities in reporting period The first decision made within the development of the KATnet strategy was that it should be aligned to the Advisory Council for Aeronautics Research in Europe (ACARE) Strategic Research Agenda 1 which contains the 2020 Vision for Aeronautics. This vision document identified the requirements for future transport aircraft and the drivers for emergent technologies. The four goals that were identified are:
• To reduce fuel consumption and CO2 emissions by 50% • To reduce perceived external noise by 50% • To reduce NOx by 80% • To make substantial progress in reducing the environmental impact of the
manufacture, maintenance and disposal of aircraft and related products. For the aerodynamics community, the first goal translates into a reduction in fuel consumption of 50%. Initial estimates suggest that from that required 50% reduction in fuel burn, half of this should come from improved aerodynamics. The first phase of the development of the KATnet strategy was to identify those technologies that could deliver against this 2020 vision goal. At the December 2002 KATnet Management Board meeting (BM1) a presentation was given of the KATnet strategy development process. Three strategy sub-teams were established - one for each of the Technology Areas A technology template together with guidelines for its completion was issued to each of the Technical Area leaders and subsequently to their strategy teams. The aim of this activity was to list all relevant technologies and to identify the so-called “Art of the Possible” for each
technology to ensure that expectations relating to the technologies were managed and to ensure that over ambitious results will not relied upon. For each technology identified, the following was required to be supplied:
• Benefit & Driver - The perceived benefit of the technology • Description – What is the technology • Component impact – What component can the technology be applied to • Technology maturity • Critical aerodynamic issues to be addressed • Critical non-aerodynamic issues to be address • Current research activities • Research gaps
A strategy meeting was held at Airbus UK in July 2003. This was chaired by the WP1 leader and was attended by the three Technology Area managers and some members of their teams. The input from that meeting was collated as the basis for the draft Technology status document. The draft version of the Technology Templates was presented to the Supervisory Board meeting (SM1) in September 2003. Feedback was received regarding the scope of the document and content. Based on the revised version of the technology templates, the Technology and Status document was prepared by the WP1 manager and issued before and presented at the Mid term review. The Technology and Status document identified the key technologies that showed promise in delivering against the 2020 vision goals and an indication of what R&T was active in supporting these technologies and their level of maturity. One difficulty that had arisen was how to differentiate between a technology (e.g. laminar flow control by suction) and a design concept (e.g. ‘high aspect ratio wing’ or ‘simplified high lift system’). KATnet has focused on technologies but clearly some classes of aerodynamic benefit are thought to be delivered through a change in the design concept that the technologies will make possible. The derivation of these benefit was seen to be a critical activity to support the development of the second major deliverable, the ‘Aerodynamic technologies: 2020 vision’ document. This second document would identify the main technological opportunities available that would make a competitive impact on aircraft performance for 2020. The technology templates issued at the beginning of the project had included a section for identifying the benefit to a future product for a given technology. For many of the technologies the TA Managers found it difficult to quantify this benefit. For example many technologies help to relax the constraints on an aircraft design and the benefit can only be realised through a subsequent redesign of the aircraft configuration. In June 2004 a technology benefit framework was developed by the WP1 manager to support the derivation of benefits. Ten aerodynamic objectives were defined based on the 2020 vision goals. Fifteen aerodynamic concepts were defined which support one or more of these objectives. Technologies can then be aligned to the concepts they enable and an
overall benefit defined. This framework was issued on the 10 August 2004 to the KATnet TA representatives for comment.
Fig. 5 Translation of 2020 vision goals into aerodynamic objectives
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DESIGN CONCEPTSLow Speed Technical AreaHigh Speed Technical Area
Fig. 6 Linking benefits to design concepts
A KATnet strategy meeting was held on 08 September 04 at Airbus UK. The Strategy framework was agreed following some refinement and subsequent actions identified. A baseline aircraft configuration was subsequently supplied for the purposes of technology evaluation. This baseline aircraft was developed within the HELIX RTD project and consisted of future projects level aircraft data such as variation of drag with lift. It had been planned to consider a supersonic configuration as well, but this never progressed.
The implications of each technology when applied to a design concept was assessed and the potential benefit was assessed along with the confidence in that benefit assessment. The results of this assessment for some of the TA2 technologies can be seen in Fig. 8.
Pot. Con. Pot. Con. Pot. Con. Pot. Con. Pot. Con. Pot. Con. Pot. Con. Pot. Con.Novel Wing Tip devices L H L HSmart structures and shape memory surfaces L H L H M M M MRiblets L HTurbulent skin friction reduction by low drag nano-scale surface finishes M Lcontrol of near wall turbulence structures by massless jets and/or surface actuation H Lcontrol of near wall turbulence structure by energy deposition (plasma). H Lapplication of distributed roughness to delay cross-flow instabilities M LHybrid Laminar Flow by continuous distributed suction M HHybrid Laminar flow by heat transfer H LActive Control of T-S instabilities by mass-less jets / surface actuation M MActive Control of cross-flow instabilities by discrete re-active disturbances M L
It is clear that this assessment needs further refinement as the knowledge relating to these technologies matures. It is also essential to appreciate the risk related to the benefits predicted for any technology assessed at the “low” confidence level. At the KATnet Board Meeting BM6 at Airbus UK on 15 March 05 the status of the 2020 technology vision document was reviewed and due to the delays encountered it was agreed that the document was not to be issued formally. It was proposed that the supporting documents from TA1 and TA2 should be issued to the partners. Since that last Board Meeting work has continued to complete the TA1 and TA2 technology evaluation documents. The TA3 team has also completed a final update to the Flow Control Technology Template document. The results that emerged from the two technology evaluation processes were used as the basis of proposals for the Technology Implementation Strategy. The aim of this final KATnet deliverable was to identify the key activities that must be undertaken to deliver the 2020 technologies. Fig. 9 shows the steps that are likely in the development of a new aircraft that has an Entry Into Service date of 2020. This “2020 Compliant Aircraft” would have flight testing and certification activities in 2019 to 2020. This would have to be preceded by a phase of manufacturing of major components and final assembly. Prior to this the detailed design of these components would have to be done. The conceptual design phase, the phase when the decision to deploy the KATnet technologies, would have to be concluded by 2015. It is therefore likely that any technology for this aircraft would have to be mature enough for concept selection by 2014.
•The implication of a 2020 compliant aircraft in service in 2020 means that technologies must be mature enough for inclusion in concept selection by 2014.
Fig. 9 Steps in the 2020 aircraft manufacturing process
The development of any technologies can be split in an extremely simplified manner into two phases. This simplification ignores the iterative process that actually occurs in the development of a technology between technology developers such as university researchers and research organisations and technology “validators” such as the aircraft companies. It is assumed that prior to 2014, any technology would have to pass through technology development and into technology validation activities. In parallel to this development activity work is needed within the aircraft companies to develop the methods to be able to implement the effects of deploying any given technology into the standard design process. This would then allow aircraft conceptual design studies to be done. This process of development and validation is represented in Fig. 10.
•Clear definitions of maturity levels are required
•UK AeIGT Technology Readiness Levels
Technology Developments
Technology Validation
Integrated design studies/benefit assessments
Fig. 10 The development and validation process prior to aircraft manufacture
It is clear from the assessments that to deliver the required step change in cruise drag, the focus of future research and development efforts must be on technologies aimed at delaying laminar to turbulent boundary layer transition and at manipulating turbulent flow structures close to the aircraft surface. The time scales involved in maturing these technologies, particularly the ability to manipulate turbulent flow structures are extremely aggressive and carry a high risk. Work is also required to develop a suitable validation platform prior to 2010 in order for it to be ready for the envisaged technology validation activities between 2010 and 2014. This is a high priority activity as it is clear that the level of confidence required by aircraft manufacturers to implement flow control technologies, as was found in the development of Hybrid Laminar Flow Control technology, is extremely high.
In addition to the work on flow control technologies, work on reducing the weight of high lift and other control surfaces should continue as this has a secondary effect on cruise drag through overall aircraft weight reduction. This means that technologies for the control of separation must be developed. Additional work is also required to consider changes in aircraft configuration that could be required as a result of deploying the technologies onto aircraft. Aircraft configurational changes were mostly out of the scope of KATnet but are important. Results / Conclusions The activities within KATnet Work Package 1 have been concluded successfully, although the timescales originally planned for have not been met. A wide range of technologies have been examined and assessed for their potential in meeting the 2020 targets. The step of applying the technologies to design concepts simplified the means of assessing the benefits of the technologies. The results of this benefit assessment were used to define the technologies for which roadmaps have been created. The KATnet Technology Implementation Strategy document contains these roadmaps relating to the development of the new technologies which the KATnet partners think are needed to enable Europe’s aircraft industry to meet the 2020 Vision targets. The technologies that are to be developed are high risk, reflecting the large scale of the challenge ahead. All parts of the research supply chain have a role to play in meeting this challenge. It is essential that research within universities and research organisations continues to identify options that can help meet the challenge. Industry must work with the technology suppliers to ensure the timely maturation of promising technologies. The implications of aircraft manufacturing timescales means that technologies for 2020 need to mature at least 5 years ahead of that date. Industry needs to define the means of validating technology maturity through the use of large scale testing including flight tests and in-service type trials. It is expected that the roadmaps should be updated after a year or two to reflect the progress made in technology development. Table 1 WP1 Deliverables
No Month due WP/Task Delivered Item
D1.1 M3 WP1 Technology Template issued to Technical Area strategy teams to capture emergent technologies.
D1.2 M12 WP1 ‘Technology Status’ document supplied to KATnet partners.
WP2 Website & Newsletters – C. Warsop, BAE Objectives for reporting period The primary objectives for Work Package 2 were to:
• Prepare and release issues of the KATnet newsletter. • Establish the KATnet web site steering committee. • Prepare a specification document for the KATnet web site. • Select a web site design company to develop and program the KATnet web site. • Initiate design and programming of the KATnet web site. • Release the web site on the WWW. • Release Issue of website with database capture of information for development of the
European research map. • Release Issue of website with communications/bulletin board facility
Activities in reporting period With the exception of the compilation of a detailed European Research Map (detailed below) all the major objectives for this work package were accomplished. Website A four-week delay in bringing the web-site on line occurred due to short delays caused by the requirement to ensure that the functionality of the web site met all long-term needs. However, the web site was fully developed in only a single step as opposed to incrementally as originally envisaged. This meant that the web-site had full functionality (including database capturing, communication and messaging features) from its initial release. The web site was structured around multiple databases making its updating and maintenance very easy. Updating could be done live online from an "administration" area by nominated individuals of the KATnet management team. The domain names www.kat-net.com and www.kat-net.net were obtained (the more obvious katnet.com etc were unavailable). The public material available on the home page included topical news items, links to conference/workshop related material, information about KATnet and member projects and links to a range of other sites of interest (including, aeronautical societies, companies, relevant conferences, research sites etc). The workshops/conferences area allowed online registration of interest in particular KATnet events and access to proceedings in electronic form. Visitors to the web site could also register for automatic emailing of conference information and newsletters. In addition to a fully public area there were three password protected levels. The first protected area ("members") was for individuals outside of KATnet to join. To join they had to provide some basic information related to their research areas, which was originally intended to form a "European Aerodynamics Research Database". Registered members had access to a number of features including:
• Searchable access to the European aerodynamics research database. • A discussion forum/bulletin board to allow them to discuss research related topics
and also comment on KATnet activities and documents. • Access to selected draft strategy documents being prepared by KATnet so that they
could contribute to their formulation. The second protected level ("partner") was for KATnet Board members/area managers to allow them to access material restricted to that group. The final access level ("administrator") enabled authorised individuals to manage and update website material, communications and transfer of documents and reports etc. During the life of the project the website was regularly maintained and updated with new and relevant material.
Fig. 11 The KATnet Home Page
Newsletters During the lifetime of the project a number of newsletters were compiled and issued. Initial newsletters were compiled as self-contained documents which, in addition to being posted on the website, were distributed via email to between four and five hundred recipients. Later in the project the size of the newsletters was reduced to provide a short paragraph of
introduction to each topic coupled with an electronic link to a more complete document posted on the KATnet website. This latter format was adopted for a number of reasons including:
• Reduction in the size of the document making email distribution easier. • Improved readability to enable greater selectivity by individuals for topics they are
more interested in. • One of the major difficulties experienced in compiling newsletters (making it a very
tedious and time consuming occupation) was the difficulty of getting suitable contributions from the community.
European Research MAP One of the key activities for the second half of the project was the undertaking of a survey and construction of a web-based database of European Aerodynamic research activities (who’s doing what, where). A similar task undertaken in the previous DragNet project had shown that this was likely to be a very difficult task to achieve successfully because it was not possible to rely on the broader research community to log into a website and spend time filling in questionnaires online. Within KATnet a different approach was tried in order to undertake the basic survey to obtain the raw material for the database. A simple MSWORD “tick box” form (see appendix) was constructed based around the taxonomy of research technologies defined within Work Package 1. This form would take at most 5 minutes to complete. The form was then issued via email to all of the four to five hundred individuals on the KATnet mailing list with a brief covering letter outlining the objectives and importance of the survey and requesting the recipient to complete and return the form. Despite sending out reminders only six completed responses were received. It was felt that so few responses could hardly form the basis of a publishable survey and because of the previous difficulties experienced with getting a response from the community for such an exercise, it was decided to cancel this activity. Results & achievements Key positive achievements include:
• The approach adopted for the development of the website was very successful. Using a responsive, professional, third party web-site developer resulted in a tailor-made product that proved to be very flexible and easy to update and maintain. The web design company worked very closely with the KATnet team to enable us to produce a very professional and useable tool.
• The KATnet web-site was regularly maintained and the site was populated with data
in all areas and membership within the general community grew steadily - albeit slowly (currently about 250 registered members). Encouraging people to visit the site and contribute material was always an uphill struggle.
• A number of KATnet Newsletters (nominally two per year) were published and
distributed via the KATnet mailing list and through the web-site.
Conclusions Development of the website and its functionality has been achieved very successfully with greater functionality being available much earlier than originally planned. The approach of employing a professional website development company has been a success. The major struggle in this activity has been to get others to provide material to populate the site and its associated newsletters. There seems a great reluctance, with a few notable exceptions, for both members of KATnet and the broader community to take advantage of the facilities provided and to participate actively in KATnet activities. Much of this was probably due to pressures of work and other commitments that exist in today's industry environment. For future reference with respect to providing guidance for future European projects:
• Use of a good professional website design organisation resulted in a high-quality tailor made solution that presents a polished end-product to the “web surfer” and a site that is flexible and easy for the webmaster to update and manage. A nominal sum of around €30-35 thousand Euros (in 2005 figures) is reasonable for such a tool development.
• The main cost of maintaining an interesting, useful and continually changing site is that of finding the material and putting it into the correct format. Insufficient man-hour allocation was made in this project and it is suggested that a minimum of 15 man weeks per year for web maintenance would be suitable for this type of activity.
• In running a communications network for this type of project the main problem is that of getting the broader community to participate and provide material and information to support the activity. In today’s current climate, individuals both in industry and academia have more than they can cope with in their normal day job that they have little interest or time to invest in providing information and support to activities that they do not perceive of bringing a direct and immediate benefit to themselves.
• Feedback from the general community (verbally at conferences etc) suggested that the “News”, “Events” and “Links” listing on the website were found to be very useful and informative. The “Forum” and project information areas were little used. Verbal feedback also suggested that the usefulness of the newsletters was limited as those with any interest browsed the website for the information they wanted anyway and those that did not read the newsletters were not interested.
• The overall effort allocated for communications between KATnet and the broader community was significantly underestimated. Future projects should perhaps consider appointing a young, enthusiastic, student/graduate for such a task with almost full time responsibility for the tracking down and preparation of material and pestering of potential donators of material.
Table 2 WP2 Deliverables
No Month due WP/ Task Delivered Item
D2.1 M3 WP2 Website concept (delivered M3)
D2.2 M6 WP2 Initial release of basic web-site (delivered M7)
WP3 Workshops & Conference – J. Fulker, QQ Objectives during reporting period
• Organise and hold first KATnet Workshop on High Lift Aerodynamics • Publish proceedings of first workshop • Initial planning for the KATnet conference • Plan and hold second KATnet Workshop on High Speed Aerodynamics • Publish proceedings of second workshop on CD • Initial planning for third KATnet Workshop on Flow Control • Hold third KATnet Workshop on Flow Control • Publish proceedings of third workshop • Hold planning meeting for the KATnet conference • Invite conference speakers • Hold KATnet/CEAS Conference
Publish conference proceedings Activities in reporting period The first KATnet workshop, devoted to high lift aerodynamics was organised and performed in Stockholm, Sweden. It was open to all interested parties working in the field of low-speed, high lift aerodynamics. Its objective was to present and discuss the status and results not only of EU funded high lift projects but also corresponding GARTEUR and national activities. Each session contained a project overview and presentations of significant project tasks. All workshop speakers, being leading European experts in that field, were invited. The workshop was adjudged a success by the workshop reviewer and attracted more than 75 attendees. Following the workshop copies of all of the presentations were collated together with brief précis to form the proceedings. These were distributed to all attendees early in 2003. In order to ensure a suitable venue for the second workshop a survey of suitable sites was carried out and the University of Bath chosen as the location. An announcement was prepared in consultation with the organising committee and the first call was distributed during February 2003 followed by further calls and a final announcement. A final programme was formulated and all key presenters invited and their presence confirmed. The workshop was adjudged a success by the workshop reviewer and attracted 100 attendees. Electronic copies of all of the presentations and brief précis were collected and published in the form of a CD and distributed to all attendees during December 2003. The final KATnet workshop, devoted to flow control was organised and performed in Poitiers France. It was open to all interested parties working in the field of flow control. Its objective was to present and discuss the status and results not only of EU funded flow control projects but also of corresponding ERCOFTAC, AIRnet (University) and national activities. Each session contained a project overview and presentations of significant project tasks. All workshop speakers, being leading European experts in that field, were invited. The workshop was adjudged a success by the workshop reviewer and attracted 130 attendees, since it was held in conjunction with an AiRnet workshop allowing cross-fertilisation of attendees.
Following the workshop copies of all of the presentation were collated together with brief précis to form the proceedings on CD. These were distributed to all attendees in early 2005. Planning for the KATnet conference was carried out throughout the period to be held in Bremen Germany 20-22 June 2005. Agreement was reached that this conference would be organised by DGLR under the auspices of CEAS and would be amalgamated with the annual RAeS aerodynamics research conference. The announcement and call for papers was distributed in February 2004 and a meeting of the conference committee was held in November 2004 to review the abstracts and finalise the programme. Around 60 abstracts were received which together with invited and plenary presenters ensured that a stimulating conference was arranged. The final programme was completed and published on the conference web site (www.kat-net2005.com) together with registration information. The two and a half day Conference was held at the Hilton Bremen, Germany. The Conference was open to all interested parties working in the field of Aerodynamics RTD. About 150 aircraft engineers and research scientists attended the workshop, including a presence from outside Europe. The Conference Proceedings collated and edited by machtWissen.de AG and QinetiQ contained the papers and the invited keynote presentations presented at the conference and were distributed to all attendees in September 2005. Results / Conclusions All planned activities have been successfully completed. Table 3 WP3 Deliverables
No Month due WP/Task Delivered Item
D3.1 M-12 WP3 1st workshop concept
D3.2 M-2 WP3 Organise 1st workshop
D3.3 M1 WP3 Hold 1st workshop
D3.4 M3 WP3 2nd workshop concept
D3.5 M6 WP3 Organise 2nd workshop
D3.6 M13 WP3 Hold workshop 2
D3.7 M20 WP3 Workshop 3 concept
D3.8 M23 WP3 Workshop 3 organisation
D3.9 M30 WP3 Hold workshop 3
D3.10 M10 WP3 Distribute call for papers for conference
TA1 Low Speed Performance – D. Reckzeh, A-D Objectives for reporting period
• Support the organisation & performance of the KATnet High Lift Workshop. • Identify the current research activities in Europe and provide input to the first KATnet
newsletter and the KATnet website. • Support the organisation & performance of the KATnet Conference Bremen • Compilation of Low Speed Performance part of the RTD strategy document (support
for WP1), see following section Low-Speed Performance – R&T Prospects In this section conclusions are given on the base of the ongoing R&T activities in Low Speed Performance with respect to the final report of KATnet Technology Template TA1. It will give a more specific summary-type description of the status, challenges, opportunities, gaps and needs of the relevant R&T concepts in order to meet R&T requirements for further research and development (especially in a European context). Therefore an overall description of each technology concept provides information for the following topics:
- status - challenges and opportunities - gaps and needs.
The different KATnet Technology templates in the domain of Low Speed Design concepts are presented thereafter in several sub areas:
- Simplified high lift system; - More effective high lift devices; - More effective control surfaces; - Unsteady flow separation and turbulent noise source; - Reduced wake vortex signature with their high-potential technology items.
Design Concept: Simplified high lift system for given Low speed requirements
- TE Camber Tabs and Mini-TED - also pneumatically (potential 5): - Separation control by the application of SBVG (potential 4) - Design Concept: More effective high lift devices for given Low speed
requirements - Novel Wing Tip Devices (potential 4) - TE Camber Tabs and Mini-TED (also pneumatically) (potential 4)
Design Concept: More effective control surfaces for given A/C control requirements
- Novel Wing Tip Devices (potential 4) - TE Camber Tabs and Mini-TED (also pneumatically) (potential 4) - Differential Flap Setting (potential 3)
Design Concept: Unsteady flow separation and turbulent noise source - Separation control by the application of SBVG (potential 5) - Acoustic treatments to airframe (potential 4). - Separation control by the application of massless jets, dynamic Dimples,
Tangential Blowing, Plasma (potential 4) Design Concept: Reduced wake vortex signature for given Low speed requirements
Technology Item Group: Design of novel devices 1 Status quo The development and improvement of single discipline driven devices reach an asymptotic point of view in research and development. So that for the design of novel devices i.e.
+ differential flap setting + TE cambers tabs and Mini-TEDs + spoiler static deflections + novel wing tip devices
modern design processes has to applied in order to gain significant changes and improvements especially for novel A/C configurations. 2 Challenges and opportunities Within the development of new high-lift devices as i.e. droop nose the variety of the development of novel devices leads to an asymptotic point of view. Otherwise new material compositions with better capabilities for structure and systems allow new design compositions in high-lift devices. 3 Gaps and needs The need for multifunctional devices in high-lift concepts leads to the requirement to solve multidisciplinary approaches – flight physics, systems and structures – for the development and the design of high-lift devices. Furthermore, the research on new materials and processes allows new possibilities in this area and stronger exchange in multidisciplinary projects would allow to rise higher potential capabilities. Technology Item Group: Flow Control Devices 1 Status quo The development of passive as well as of active flow control devices is acting on aerodynamics, aeroacoustics, system and structure requirements for the design of high-lift devices / components. Simple devices i.e. Mini-TEDs for aerodynamic improvement or vortex generators for aeroacosutic improvement (reduction of tonal noise) are well understood. Another devices / technologies like jet-flow control, tangential blowing, plasma actors seem to be more complex techniques and very future devices for a real A/C. Therefore noval flow control devices should be focussed on simple devices which could be nice integrated in structure and system concepts of a real A/C.
2 Challenges and opportunities Due to the up to now mostly single coordinative operation of several disciplines the requirements and opportunities as well as their consequences for the overall aerodynamic design and performance of an A/C are not fully known. 3 Gaps and needs The technical requirements of flow control devices should be clearly discussed in the TA groups and partners to evaluate conceptions which probably lead to an application on a real A/C configuration. Multifunctional requirements need in this case also a multidisciplinary work on these technologies. Technology Item Group : Aerodynamic-aeroacoustic design 1 Status quo An important driver in the design process of high-lift components is and will be the aerodynamics beside structure and systems. For single evaluations it was shown that also the aeroacoustics plays an important role in this design process. Furthermore noise emission becomes/is an economic key factor for the cost evaluation of A/C configurations and their mission portfolios for Airlines. 2 Challenges and opportunities Due to the further development of methods and tools in aeroacoustics (CAA) the aeroacoustics is involved a design process which strongly coupled with the numerical simulation of the aerodynamics (CFD). A variety of CAA methods are developing although one or two concepts could available for industrial application. 3 Gaps and needs In order to realize a closed loop of CFD and CAA it is necessary to develop the CAA tools closed to the CFD capabilities and vice versa to gain a comprehensive aerodynamic-aeroacoustic design process esp. for high-lift components, because the most simulations based up to now on 2D configurations. But, it is necessary to evaluate these tools for 3D configurations and to improve these tools as not cost intensive tools, if one of these codes would entry in the industrial design. Summary In all three categories of technology item groups wrt the low speed research areas it can be summarized that: 1) aerodynamics, structure and system has to communicate and work more and more
together to reach new solutions for the design of high-lift components in order to improve the aerodynamic performance of an A/C and/or to be prepared to the requirements for the development of novel A/C configurations.
2) aeroacoustics plays for the development of high-lift devices in the short-term for landing,
but in mid- and long-term also for start procedures a more and more important role. Therefore, it is necessary to implement the aeroacoustics in the aerodynamic design process starting at single and well-know configurations and devices, and further towards
complex devices in order to evaluate the aerodynamic-aeroacoustic design process for industrial application.
Activities in reporting period Workshops & Conferences The KATnet High Lift Workshop took place on 17-19 Sep 2002 at Bosön Conference Centre Stockholm, being the first of three workshops within KATnet. Although placed already in the starting period of KATnet the successful workshop had a very good participation with lectures about results & developments from various high-lift related R&T programs. The KATnet Kick-off Meeting was organized in combination to this event. Broad attendance from TA1 representatives was provided also to the high-speed workshop in Bath and especially also the flow-control-workshop in Poitiers. Support from TA1 was given to the preparation & organisation of the KATnet conference. Significant contribution with lectures on high-lift topics could be given to the conference. Two designated high-lift sessions took place. The conference proofed to be a valuable platform for exchange within the high-lift community. TA1 representatives also conducted a site tour through the Airbus High-lift Development & Integration centre in Bremen. Dissemination of information The TA1 partners have also contributed to the content of the KATnet newsletter and the layout & content of the KATnet website prepared in WP2. Information about KATnet was widely distributed inside the European low-speed aerodynamics community leading to a good appreciation of KATnet. Research Strategy The current European research activities concerning low speed aerodynamics have been identified within this Technology Area. These results were used as input to the strategy development performed in WP1. Recent information of the content & status of European and national R&T Programs was collected from the TA1 sub-area managers, resp. the related program managers. The low-speed performance part of the RTD strategy was compiled by Airbus D and discussed on a KATnet strategy workshop inside the management board. The content of the RTD strategy list was further refined and aligned with the Airbus needs. EUROLIFT 2 contents and IHK (German national) contents were mirrored in the KATnet TA1 activities, i.e. reflected in the RTD strategy. TA1 representatives participated in further KATnet strategy meetings to support WP1. The final comprehensive TA1 strategy document was completed & delivered in Oct 05.
Preparation of future R&T programs Participation of TA1 representatives was held in the preparation of proposals for EU FP6 R&T-programs (as NACRE, FLIRET and JAWS). Also intensive discussion & exchange took place in the low speed community on potential low speed contents for FP7 programs. Further the KATnet low speed strategy served as background for the discussion of contents for oncoming national funded German R&T program LUFO4. Results / Conclusions All objectives for TA1 could be reached. Table 4 TA1 Person hours
Partner Person Hours used until month 39
Person Hours available* for total period
A-D 402 402 A-UK 200 201 DLR 289 229 FOI 239 239
TOTAL 1130 1071 * as in KATnet DoW
Table 5 TA1 Deliverables
No Month due WP/ Area Delivered Item
DA1.1 M12/24/36 TA1 TA1 contribution to strategy development DA1.2 M18 TA1 TA1 input to European Technology Map DA1.3 M1 TA1 Scientific support for TA1 Workshop DA1.4 M30 TA1 Scientific support for KATnet Conference DA1.5 M3 TA1 TA1 website content
TA2 High Speed Performance – D. Sawyers, A-UK Objectives for reporting period The objectives of Technical Area 2 High Speed Performance were as follows:
• To act as a hub for information exchange for the activities in this topic area. It was intended encourage information exchange between people working on the different projects within this topic area. It was planned that this would include encouraging strong participation in the High Speed Performance Technical Workshop and the KATnet Conference, in supporting the updating of information on the KATnet website and in sharing publishable results from the partner projects within the KATnet membership.
• To support the development of future research and development strategies. It was intended to participate in the strategy development team led by the WP1 leader, Stephen Rolston, contributing expertise as required to ensure the successful completion of the WP1 deliverables.
• To establish sub-area interest groups and initiate interest group activities. The three sub-area co-ordinators within Technical Area 2 were expected to set up sub-area interest groups so that technology developments within these sub-areas could be discussed. Activities in reporting period
• Support to the development of the KATnet research and technology strategy The Technical Area 2 team contributed to all three phases of the WP1 Strategy Development activity. The first phase consisted of completion of the High Speed Performance technology template document, which was supplied to the WP1 manager, prior to the development of the Technology and Status document. In the second phase, the benefits of applying different technologies to a generic aircraft were assessed. This resulted in a TA2 Technology Evaluation document that ranked technologies of High, Medium and Low potential and also the confidence in these assessments was also ranked. In the third phase, the steps required to develop cruise drag reduction technologies were considered and this information was supplied to WP1.
• Dissemination of topic area information The following EC programmes were identified within the KATnet Description of Work as belonging to TA2.
In addition it was expected to include relevant GARTEUR, ERCOFTAC and National funded projects. The major national project that was identified was the UK DTI-funded project NEXUS, led by Airbus UK with the participation of QinetiQ. The researchers within these projects were encouraged to participate in the KATnet High Speed Performance Workshop that took place at the University of Bath in September 2003 and in the KATnet Conference in Bremen, June 2005. The members of the TA2 management team participated in the activities leading the co-ordination of these two events, including reviewing abstracts for the conference. At the Workshop, the Technical Area manager and sub-area 2.2 manager, V. Selmin (Alenia), acted as session chairmen. The participation of Airbus UK speakers to discuss HiReTT, M-DAW and NEXUS projects was ensured by Airbus UK. Members of the TA2 team also contributed as requested to the update of information on the KATnet website. Supply of information to the website was subject to approval by the Airbus UK communications team and therefore the process was not as fast as was desired. In addition, the TA2 manager provided regular updates on project progress to the members of the KATnet Management Board and Supervisory Board through presentations at the relevant board meetings throughout the duration of the project. The Technical Area manager attended the Royal Aeronautical Society Aerodynamics Research conference 2004 and acted as a Chairman for a session on configuration topics. At the conference he highlighted the presence of the KATnet website and encouraged all attendees to sign up to membership via the website. Contacts with similar Europe wide groups with interest in aerodynamics research were explored with initial discussions being held with members of EASN. An invite was received to attend an EASN meeting but unfortunately this could not happen due to prior work commitments.
• Support to the development of the European Technology Map It had been intended that a European Technology Map would be developed within WP2 but this did not happen. This meant that the information that was required to launch the sub-area interest groups was not available and hence this activity did not take place. Results / Conclusions The Technical Area 2 team contributed as required to the success of the KATnet project. The participation of Alenia and Airbus France was useful but it was felt that the role of sub-area manager was something that could have been improved upon. In the end the sub-area managers just acted as representatives of their organisations and not representing the technology sub-areas as had been planned. Another set back to the success of this Technical Area was that two of the three EC projects, namely HiReTT and Aeroshape, concluded early on in KATnet timescales and it proved difficult to introduce potential replacement projects such as REMFI, because Airbus Spain, REMFI’s co-ordinator were not part of the KATnet consortium.
DA 2.1 M3, M12 TA2 Area 2 contribution to KATnet strategy development – Stage one completed
DA 2.2 M18 TA2 Area 2 input to European Technology Map – definition of input required from WP2
DA 2.3 M13 TA2 Scientific support to Area 2 workshop - completed DA 2.4 M34 TA2 Scientific support to conference. Note conference shifted to 2005 DA 2.5 M3 TA2 Area 2 website content defined – updates as appropriate
TA3 Flow Control Technologies – J. Reneaux, ONERA Objectives for reporting period The objective was to identify the current research actions in Europe as far as flow control technologies are concerned. Relevant European projects as well as some activities within national programmes have been considered. The TA3 team has also contributed to the strategy document of the WP1 in particular by writing the technology templates for the flow control Technology Area. Activities in reporting period Recent activities in the field of flow control technologies related to laminar flow control, turbulence and separation control and adaptive wing concepts have been summarised in the KATnet technology template. The purpose of this document is to consider each technology in order to provide information for the following topics: benefit & driver, description, component impact, technology maturity, critical aerodynamic and non-aerodynamic issues to be addressed to mature this technology, current research activities, and research gaps. The technology template has been written by the TA3 manager and by G. Schrauf (Airbus Deutschland), C. Warsop (BAE SYSTEMS) and H. Bieler (Airbus Deutschland) respectively for the three sub-areas: laminar flow technology, turbulence and separation, adaptive wing concepts. The 22 technologies considered have been selected for their possible contributions to the “2020 vision”. Discussions took place in many meetings in connection with WP 1 manager (S. Rolston) in order to prepare the strategy document: Supervisory Board meeting the 5th of September 2003 in Bath, Mid-term meeting the 10-11 March 2004 in Bedford, the strategy meeting the 8th of September 2004 in Filton, the Supervisory Board meeting the 14th of October 2004 in Poitiers. The TA3 team has contributed to the strategy by evaluating the benefits which could be obtained with the different technologies and by identifying the links between the technologies and the aircraft/component concepts. ONERA and the TA3 team also contributed to the preparation of the KATnet workshop devoted to flow control and to the Bremen conference. The Flow Control Workshop was held October, 12-13, 2004 in Poitiers, the Bremen KATnet conference, the 20-22 June 2005. TA3.1 Laminar Flow Technology – G. Schrauf, A-D Airbus D. has supplied in this area a contribution to TA3 on Laminar Flow Technology. The status is based on European projects such as ALTTA, TELFONA and SUPERTRAC, as well as Airbus D. in house studies. The Hybrid Laminar Flow Technology considers a simplified suction system. The main idea of this simplified suction system is to use a double skin structure for two purposes: to support the micro perforated suction surface and also to obtain the desired pressure drop through the suction surface. Studies have shown that the gains due to the drag reduction remain positive even if the additional weight and the addition energy consumption of the suction system are taken into account. Alternative technologies have also been considered and the micron-sized roughness elements concept is a very promising one.
TA3.2 Turbulence and separation control – C. Warsop, BAE-S BAE SYSTEMS contributed strongly to the preparation of material for the KATnet Newsletters, attended KATnet board meetings to discuss formulation and preparation of the strategy documents produced within WP1. BAE SYSTEMS also participated in the organisation and execution of all three KATnet Workshops and the KATnet/CEAS Conference held in Bremen in 2004. The company also assisted in the compilation of the KATnet mailing list to capture individuals working in the flow control field. BAE SYSTEMS was also strongly involved in the formulation of the strategy document (WP1), especially to the "turbulence and separation control" sub-area. To do this BAE SYSTEMS participated in workshop meetings and the completion of technology templates. Activities also included the preparation of material in this technology area on the KATnet website. A significant contribution was also made by BAE SYSTEMS to preparation and execution of the KATnet Flow Control Workshop held in Poitiers in October 2004. This included the organisation of sessions on the AEROMEMS projects and contributions to other sessions on UK research activities. In addition to the scheduled KATnet events efforts have also been made to organise turbulence and separation control sessions in conferences held in the UK (Royal Aeronautical Society aerodynamics conference in September 2004 and in the USA (a session on UK flow control activities was organised for the AIAA 2nd flow control Conference held in Portland in June 2004). Two European flow control sessions (16 papers) have also been jointly organised by BAE SYSTEMS and Airbus UK for the forthcoming AIAA 3rd Flow Control Conference to be held in San Francisco in June 2006. In preparing the Technology Templates for TA3 it has been concluded that turbulence and separation control is an area that has potential for significant advances to be made for meeting the “2020 vision” targets for emissions. While this area provides opportunities for significant reductions in turbulent skin friction drag to be realised through the control of near-wall turbulence it remains one of the most technologically challenging areas and will require substantial investment in Research and Development activities over the coming years. TA3.3 Adaptive wing concepts – H. Bieler, A-D In co-operation with other sub-areas, current research activities related to adaptive wing concepts have been reported in the technology template. Airbus D. has supported the WP1 technology strategy and delivered information for the following topics: multifunctional control surfaces, trailing edge devices, shock control devices, wing tip flow control, smart surface, virtual shaping. Airbus D. attended the strategy meetings and KATnet board meetings. In addition, a detailed presentation of national German R&T activities was held at Poitiers KATnet Flow Control workshop.
Examples of flow control technologies The considered technologies are listed here for the different sub-areas with an illustration of a promising concept. Laminar Flow Technology
Hybrid Laminar flow by mass transpiration
Laminar flow by micron-sized roughness elements
Hybrid Laminar Flow by heat transfer Active control of Tollmien-Schlichting by
mass-less jets / surface actuation
When micron sized roughness elements are placed in the critical region near the leading edge, with suitable pressure gradients and wavelengths of the killer vortices, non linear interactions between natural and killer vortices yield the decay of the amplitudes of both vortices
Example of stationary cross-flow vortices on a swept wing
Turbulence control
Turbulent skin friction drag reduction by Riblets
Turbulent skin friction drag reduction by LEBUs
Turbulent skin friction reduction by active manipulation of near-wall turbulent structures (MEMS)
Turbulent skin friction drag reduction by micro-blowing
Separation control using vane vortex generators (passive, deploying and sub boundary layer scale)
Separation control using air-jet vortex generators (steady, unsteady positive and zero mass flux)
Separation control by active manipulation of near-wall turbulent structures (MEMS)
Separation control by active manipulation of separated shear layers
Separation and circulation control using tangential blowing (steady and pulsed)
URANS simulation of synthetic jet effect on separation
Application to high-lift devices with drooped leading edge slat
Adaptive wing structure
Shock control devices Differential flap setting Acoustic treatment to slats and flaps Multi-functional control surfaces,
trailing edge devices Wing tip control Smart surface Virtual shaping
Non conventional sensor / control surfaces
For each technology, a template has been established to provide information for the following topics: benefit & driver, description, component impact, technology maturity, critical aerodynamic and non-aerodynamic issues to be addressed to mature this technology, current research activities, and research gaps. The relations between the technologies and the design concepts considered in WP1 have been identified and the potential levels of benefits estimated.
Summary of flow control technologies The link with TA1- Technologies relevant to the low speed regime – is underlined with the following table. The different technologies are distributed depending on the possible applications and the level of maturity.
More efficient or simplified high-lift and control surfaces
Reduction of noise source Reduction of wake vortex
For the low speed regime it can be concluded that: - Many low speed design concept are based on technologies related to separation control ; - Flow control technologies could allow the striking of a better balance between the
efficiency of the aerodynamic devices and their impact on the environment (noise, wake vortex).
The link with TA2 – Technologies relevant to the high speed regime – is presented in the following table depending on the drag components and the level of maturity.
Understand Smart surface Nano-scale surface finishes Control of near wall turb. structure by massless jets Skin friction reduction using plasmas Distributed roughness to delay C.F.I. HLF by heat transfer
For the high speed regime it can be concluded that: - Current technologies cannot satisfy the objectives of the 2020 vision ; - Many immature technologies are related to skin friction. Need to understand the flow
physics and to develop new practical concept. Conclusions and lessons learned The Technical Area 3 team has contributed strongly to the KATnet project mainly with the elaboration of detailed technology templates. For future thematic network, it will be worthwhile to organise thematic workshops with a limited number of specialists to determine the state of the art of one technology and to undertake brain-storming with a multi-disciplinary approach. Moreover, as the benefits offered by one technology depend on the chosen configuration, there is a need to establish realistic reference configurations for the control activities. The KATnet network has also initiated fruitful discussions between the different potential partners and has helped to elaborate the technical proposals of many projects. The main European projects related to flow control proposed during the KATnet thematic network activities are the following: - SUPERTRAC (micro-sized roughness, laminar flow) - NACRE (innovative configurations) - AVERT (fluidic jets, MEMS technology, new trailing edge device, dimples, low energy
plasma, micro-roughness in turbulent) - FLOCASSIR (dynamic stall control, low energy plasma, active bumps, micro-vortex
generators) - TIMPAN (drooped nose and air-jets for high-lift devices, low energy plasma and air-jets
for landing gear) - LONDON (low noise nacelle technologies, optimized acoustic liner arrangements,
scarfed nozzle) - ITALIA (non conventional sensor/control surfaces to enhance loads and aero-elastic
Management & Co-ordination Aspects KATnet has been managed on the basis of its project management structure, Fig. 7 of the DoW, and the Consortium Agreement, signed by all partners. After counter-signature of the KATnet contract by the EU mid of Nov 2002, the 1 Sep 2002 was confirmed as commence-ment date of KATnet.
Fig. 12 KATnet Meeting Schedule
The KATnet meeting schedule, Fig. 12, shows the main project meetings performed during the course of KATnet. As far as possible the Management Board meetings were arranged in conjunction with other KATnet events. The Kick-off meeting devoted to the discussion of the KATnet work programme and the start of the initial networking activities took place on 17 Sep 2002 at FOI Stockholm just ahead of the first KATnet workshop on High Lift Aerodynamics. QinetiQ and FOI committed to the workshop preparation before the KATnet contract was signed. The workshop which attracted more than 75 attendees was seen as a promising start of KATnet. The first and second Management Board meetings aiming on the networking activities of the first year took place on 10 Dec 2002 at Airbus Bremen and on 13 May 2003 at ALENIA Turin respectively. On request of the Commission, a KATnet Supervisory Board recruited from senior personalities of the KATnet partner organisations was established. The first Supervisory Board meeting took place on 5 Sep 2003 at the beginning of the second year of KATnet at
the University of Bath, UK just after the second KATnet workshop on High Speed Aerodynamics. This workshop which attracted nearly 100 attendees became a big success. The Midterm Review meeting was performed on 11 March 2004 at QinetiQ Bedford. The progress of the network was assessed with the result to continue with the KATnet activities. The fourth Management Board meeting on 10 March 04 was dedicated to the preparation of the Midterm Review. The third year of KATnet started with a workshop on Flow Control Technologies, the fifth Management Board Meeting and the second Supervisory Board Meeting held on 12-13, 13 and 14 Oct 2004 respectively at the University of Poitiers, France. The third KATnet workshop attracted about 130 participants since it was held in conjunction with an AIRnet forum on flow control allowing cross-fertilisation of attendees. The next major KATnet event was the CEAS/KATnet Conference on Key Aerodynamic Technologies held on 20-22 June 2005 in Bremen, Germany. The theme of this conference was to present and discuss aerodynamic technologies that open up to meet the challenges of the Vision 2020. Agreement was reached to organise this conference together with DGLR under the auspices of CEAS and to amalgamate it with the 2005 RAeS Aerodynamics Research Conference. The Announcement & Call for Papers was distributed in Feb 2004. The Programme Committee meeting was held in Nov 2004 in order to review the abstracts and to set up the conference programme. The conference was attended by about 150 aircraft engineers and research scientists including a presence from overseas, who adjudged the conference as a world-class event. With two exceptions – preparation of the KATnet strategy documents in WP1 and compi-lation of the conference proceedings in WP3 – that could not be completed within the contracted period, the KATnet targets have been achieved. Therefore the KATnet consortium asked the Commission for an extension of the KATnet contract by four months to 31 Dec 2005 which was accepted. The KATnet Final Review meeting – in conjunction with the third Supervisory Board meeting – is scheduled for 30 Nov 2005 at Airbus D in Bremen. The final KATnet strategy document will be presented there. On the day before a Final Review Preparatory meeting will be performed with the Management Board members. Table 10 Total Person Hours
A KATnet handbook has been prepared, regularly updated and distributed containing all relevant information for the co-ordination of the project including contact details of the partners of the KATnet member projects.
Fig. 13 Overview on KATnet person hours used
No cost problems have been reported during the lifetime of KATnet. The used person hours in the different WP’s and TA’s as presented in Table 10 and Fig. 13 are well corresponding with the work progress reported above. Conclusions The main objective of KATnet was to identify and assess those aerodynamic technologies that are needed to meet the Vision 2020 goals and to be the European focus for these technologies. This was reached by development of a common R&T strategy in the KATnet technology areas and by providing a communication platform via Internet, workshops and a conference on the subject. Successful networking activities have been undertaken to reach this ambitious objective, but further efforts are needed to refine and complete the KATnet achievements.
that are promising a step change rather than a small benefit will enable Europe’s aircraft industry to be competitive in the future. • The technologies that have to be applied and validated are high risk. Each technology
has to prove its maturity for industrial application in an intensive flight test programme. • The implications of aircraft manufacturing time scales mean that technologies for 2020
need to mature at least 5 years ahead of that date. • It is therefore likely that any technology for a “2020 Compliant Aircraft” has to be mature
for selection by 2014 leaving a few years only for technology development and validation. • Industry has to co-operate with the technology suppliers to ensure the timely maturation
of promising technologies. A strong involvement of all parts of the research supply chain is essential.
KATnet Website & Newsletters • The KATnet homepage and newsletters were important means for the dissemination of
KATnet information. • A very professional website has been developed, but the site population was weaker than
expected. The major struggle in this activity was to get others to provide material to populate the site and the associated newsletters.
• The overall effort to maintain an interesting, informative, and permanently updated website was significantly underestimated.
KATnet Conference & Workshops • The communication platform provided by workshops on key technology areas and an
international conference on the subject was very successful due to the presence of many European initiatives, their thematic relevance and their perfect organisation.
Generally it was felt that KATnet has well contributed to the improvement and enhancement of European collaboration in aeronautics to reach the Vision 2020 goals.
Lessons Learnt During the course of KATnet lessons have been learnt how to improve the networking activities of a potential successor:
R&T Strategy Development & Exploitation The whole KATnet strategy development procedure should be refined and completed con-cerning multidisciplinary technology evaluation, implications of the “2020 Compliant Aircraft”, and the development of roadmaps for the technology implementation into future aircraft. • The existing technology templates are a valuable database for more detailed strategy
investigations. • For industry “confidence in a technology” seems to be a guide rather than the “degree of
technology maturity”. • For a more reliable quantification of the potential benefits a multidisciplinary approach is
needed. • As further items in the strategy development
aspects have to be included. • The implications of the “2020 Compliant Aircraft” are dictating the timescales for the
technology development & validation. The academic & research community has to be fully incorporated into the corresponding efforts.
• The development of realistic roadmaps including the definition of a dedicated technology validation platform for the timely maturation of promising technologies should be the main focus of the follow-on activities.
KATnet Website & Newsletters • The very professional homepage which has been established in KATnet should
intensively be used as communication platform of the KATnet successor. • The efforts needed for the communications between a KATnet-type network and the
broader community have to be considered in the follow-on project. • Electronic newsletters should more frequently be edited than in KATnet.
KATnet Conference & Workshops • The successful conference & workshop philosophy of KATnet should be continued. • In addition, technical seminars & smaller workshops on more sophisticated topics should
be organised in conjunction with the administrative meetings.
Kenneth Nilsson, Saab AB, Head of Applied Aerodynamics, retired General The workshop was well organised, interesting and promising. The papers given were generally good and well presented and adhered, with few exceptions, to the schedule. But most papers contained too much information, as is often the case under these circumstances! It was a pleasure to attend and a privilege to give the final review! Background Aerodynamic efficiency has a great impact on aircraft operating economics. Roughly some 50% of the Direct Operating Cost, DOC, of an airliner is connected to the weight/cost of the aircraft. Of that, approximately 5%-units stem from the nonrecurring costs of which aerodynamic development is less than 10% i.e. <0.5% of DOC. Some 20% of DOC are fuel costs. About 40% of weight/cost of an airliner are effected by aerodynamics. Thus a 1% increase in the aerodynamic efficiency (L/D) may be paid by up to an 80% increase in the aerodynamic development cost! �(50�0.4+20)/0.5�. But likewise a reduction in the dispatch reliability or increase in maintenance due to a complex "aerodynamic system" can cost dearly. This is the background to the importance of "attention to detail" and "to keep systems simple". High Lift Perspectives The two papers given by Henke and Jupp respectively gave a good and quite necessary introduction to the subject. This is important so that people involved can see the broad view and get the focus right. The importance of attention to detail and simplicity was underlined. High lift design is a multidisciplinary activity Aerodynamic work involves many disciplines like structure and systems but is also multidisciplinary within the aerodynamic community. For years a certain animosity has existed between the experimentalist and the theorist which probably has been accentuated with the advent of CFD. This is a highly unfortunate situation. Thus it was pleasing to note that several programmes, like EUROLIFT, HiAer, ProHMS, NEXUS and others have a close interaction between the various disciplines. In a sense aerodynamics is still in its infancy; data where they are needed most (CLmax, CD, CH) are notoriously hard to come by. Therefore several sources are therefore needed, still spiced by some black art! Aerodynamic design work is done early Most aerodynamic design work must be done early – in fact so early that the other disciplines are barely aware that there is a programme! Unfortunately it also takes TIME. Accurate CFD-calculations require often many months. Good windtunnel models take a lot of time and effort to build. And much iteration is needed. This is worthwhile (see above!) but the aerodynamic community must bring this knowledge forward to the people who have the key to the treasure chest. The workshop should produce results, which help to explain these facts.
Flight testing and certification Reynolds number, surface conditions, support structures and other full-scale parameters may have a great influence on high lift performance. Still much too little experimentation is done in this field. It seems of great importance that the tests now proposed, albeit costly, can be carried out. Certification is an expensive exercise, which might be improved through better prediction of high lift performance including stall characteristics and other phenomena e.g. buffeting. It is suggested that this field be taken under special consideration, if not already done. Operating conditions Operating conditions like icing, wake vortices and steep approaches where addressed in various papers. This is very good and the proposed "ice workshop" should be organised soon. Other aspects mentioned which require attention is comfort, noise and vibration. Flying is ridiculously uncomfortable compared to most other modes of transportation and improvement is necessary! DRAG Drag is the aerodynamicist's number one enemy! Although drag was certainly mentioned at the workshop it seems that it was often given too little attention in the presentations. This must be changed since accurate data are hard to come by both in calculations and tests. Views on the papers as a whole The papers given gave a good coverage of the field and represented a relatively good balance between theory and experiment. Still a few subjects need underlining e.g. drag, tail design, stall characteristics and complete configurations. Also subjects like comfort and "the ecological airliner" should be pursued more vigorously in the future. New ideas Evolution AND revolution is necessary! Evolution is relatively well in hand but how to create a revolution? It will not come on command but can be encouraged. HELIX is a necessary programme, which may very well fail! But only to rise as HELIX 2…and 3 and…. "The ecological airliner" is another theme, which is likely to influence high lift, maybe in an unexpected way. Brainstorming is proposed! Organisation/funding Airbus has for a long time dominated the European aeronautical landscape. Possibly rightly so. But there are still a few other players and they must not be forgotten. However the real risk is complacency and short-sightedness on the part of Airbus. With the A380 development at full steam and the A400M well on its way, managers may believe they can slow down on research. Wrong!! Aerodynamic work takes time and a revolution is to be encouraged! And with all the mergers there is a great opportunity to save money!…or?? NO, keep up industry- and EU-funding; involve research organisations and universities. Keep the national programmes alive but exchange results and keep GARTEUR going. A lot can be spent on cost effective aerodynamic development and that must be brought to bear on the "managers". Last but not least: create a creative environment through less bureaucracy both in industry and "at the Commission"! Let a thousand aerodynamic flowers blossom!
Attachment 9 High Speed Aerodynamics Workshop Final Review
Review of Second KATnet/GARTEUR Workshop High Speed Aerodynamics, University of Bath, 3-4th Sep. 2003
Prof. Jeffrey Jupp - Director Technical Airbus UK (Retired)
General This Workshop follows and complements the first on Low Speed Aerodynamics in Stockholm in Sep 2003. Perhaps not surprisingly, many of the general issues arising were very similar, of which more below. The arrangements for the workshop were excellent, with thanks to all concerned. It generally ran to time with good, relevant presentations and was clearly much appreciated and enjoyed by most and probably all participants. However, a note on “housekeeping” may be useful for further similar occasions. The value of such a workshop is as much in the discussion and questions as in the presentations themselves. In order to keep to time, the session chairmen had often to limit questions due to the presentations overrunning, and particularly the presenters on specific Framework projects appeared to spend a lot of time in reviewing the organisation and setting up of the work done, to the detriment of reviewing the results achieved and/or the following question/discussion time. Also, on several occasions, due to the need to move on, the audience was left trying to understand quite complicated charts etc. with unreadable scales and/or poorly differentiated colours for lines on graphs without being “taken round” the information displayed. The message is perhaps obvious and applies to many such occasions, please restrict the presented material to the important points of interest to the audience (remembering that fuller information can be put in the proceedings), do a dummy run to get the timing right and use good clear graphics readable from the back of the lecture theatre (or leave enough time to explain thoroughly)! None the less, the fact that the questions were being asked, and the various discussions that were taking place “in the corridors” was evidence of the involvement of all the participants in what was clearly a worthwhile event. Perspectives The introductory remarks by Thiede/Knoerzer, and indeed the final presentation (before the round table discussion) by Rolston, “set the scene” for the requirements for the high speed aerodynamic contribution to future air transportation systems, and the support mechanisms to help achieve it. “Vision 2020” and the resulting ACARE targets now give the goals to be sought by the Industry, as was pointed out, over the remaining 17 years! The relevant Targets for this workshop were the halving of both CO2 per passenger kilometre and the perceived noise levels for take off and landing (relative to the year 2000 fleet). The former translates into 50% fuel burn reduction (from airframe plus propulsion system efficiency of course), as possible alternatives to hydrocarbon fuels are seen at present to be outside the target timescales. Noise reduction is relevant to high speed vehicle aerodynamics through possibly requiring novel aircraft/propulsion system configurations for noise shielding, which
will be very demanding of integrated aerodynamic solutions (e.g. the SEBU presentation). As these goals can only be approached let alone met by a combination of aircraft re-optimisation to today’s technology base, and both evolutionary and step change new technologies, the time for fundamental research work is now very short! Therefore maximising the opportunities and best use of available resources, both human and financial and whether in Industry, Research Establishments or Academia, will be absolutely key, as was referred to by Knoerzer and several times through the workshop. Chu’s presentation then moved on to some of the more explicit drivers for the high speed aerodynamicist: - the need to look for the right optimum solution including weight and cost repercussions; the need for accurate drag prediction/measurement; the need for CFD capability to deal with “Whole Aircraft” configurations (gone are the times when one could optimise a wing or even wing-body combination in isolation!). Also of importance to the manufacturer was then the need to define all aircraft surface shapes rapidly through CAD tools and translate into robust meshing for CFD codes. “Integration” As for the first workshop, a key theme running through this one was “Integration” in several senses. Firstly, the need to integrate research projects and resources, and a “road map” to fulfil the ACARE vision and targets. No immediate solution here, but perhaps a role for a working group under ACARE from KATnet participants to co-ordinate research between EU and National plans, using Industry, Research Establishments and Academic resources throughout Europe to best effect. The future role of GARTUER was also raised now ACARE was in place. It was recognised however that GARTEUR could help bridge between Civil and Military requirements to bring yet further efficiency. Secondly, the need to deal with the aircraft aerodynamic solution as a whole and (from several presentations) the emerging ability of CFD to be able to do exactly that. It was interesting to note just how far CFD has improved in this capability, even in the last five years, with improvements in meshing schemes etc, although the cost and turn-around times for complex configurations still leaves room for improvement! Thirdly, “multi-disciplinary” optimisation. To reduce fuel burn, let alone to obtain the most efficient solution regarding cost as well, the optimum aerodynamic solutions must involve the effect on structure weight as a minimum. This was clearly demonstrated in a supersonic example (CISAP) where the baseline configurations re-optimised towards lighter weight solutions and where allowing for landing gear stowage had a major effect on the optimum wing envelope. Other examples were given (M-DAW and MegaFlug) of wing devices that reduced drag but increased wing bending moments, making an Aero-Structural optimisation mandatory. Also, if the devices were moving surfaces, then the installation and the cost, weight and maintainability of operating systems needed to be taken into account. Thus a major output of purely Aerodynamic projects was seen as the “Trade-off” data to be input into fully multi-disciplinary projects for integrated solutions. Validation Several presentations addressed the issue of validation, both of CFD codes under development and the latest experimental facility, the High Reynolds Number Cryogenic
European Transonic Wind Tunnel (ETW). The use of CFD to look at constraint and support corrections in ETW was noteworthy (HiReTT). Much good work in gathering experimental data (at high Re.No.) had clearly been achieved, the emphasis now being on the analysis and incorporating into the CFD code development. Concern was expressed (GARTEUR) that full value for the costly experimental work may be missed if continuing support was not maintained for the fundamental research work of analysis and code improvement. This was an area where full use of Academia could certainly bring value (e.g. the “Turbulence Modelling” example). It was also clear that wind tunnels will still be required for a long time yet and validation of both CFD and Wind Tunnel testing will continue in importance. In the latter context, the recognition of model deflections under load (HiReTT) and progress with Pressure Sensitive Paint (GARTEUR) were of note. Drag Prediction and Reduction Examples were given of the importance of extreme accuracy of drag prediction required for both subsonic and supersonic civil transports (i.e. to better than 1 drag count). Good progress has been made in the ability to extract drag from CFD (ONERA), but the turbulence modelling problem in Navier Stokes codes is still an issue. The repeatability achieved in ETW was encouraging, as was the work to validate corrections. Several examples of work to reduce drag, both theoretical and experimental, were shown, but as was pointed out in closing discussions the totality of the potential improvement being addressed was relatively low compared with the ACARE target and was mainly in the ”Evolutionary” field. Rolston pointed out that we had seen very little regarding profile drag reduction, and made a plea for far more attention to reducing turbulent skin friction (as well as reminding all of the work done in recent years on laminar flow). This does appear to be a serious gap! Jupp also commented that parasitic drag had not been mentioned (i.e. drag due to manufacturing gaps, steps etc on the surface of the aircraft) and perhaps CFD had now reached the stage where the old drag database could be updated to give a more scientific basis for design rules in modern transonic flow applications. Round Table Discussion and Conclusion As well as reviewing some of the above points, the concluding discussion came back to the ACARE targets. Would the Airlines be prepared to pay for the “Green Aircraft”, was the 50% fuel burn reduction anywhere near achievable? The research community must assume that the Airlines will require such an aircraft, due to the impact of new regulatory mechanisms if so be it (and the precedent of airport noise limits should be noted!). Although the 50% fuel burn reduction is certainly a stretch goal, it is by no means out of sight with such technologies as open rotor propulsors and hybrid laminar flow already “on the shelf” and capable of delivering a large share! This workshop provided an excellent step along the road for the contribution of the Aerodynamicist to reach the new goals, but there is equally clearly much more to do, demanding the most efficient use of resources throughout the European Aerospace community and Academia.
FINAL REVIEW CEAS/KATnet Conference on Key Aerodynamic Technologies
20 - 22 June 2005, Bremen Egon Stanewsky, Senior Scientist, DLR ret.
Objective KATnet comprises activities in key aerodynamic technologies carried out in European national Research Institutions, Academia and Industry mainly in European cooperations and national programs. The objective of the Conference – seen as successor of the CEAS/DragNet European Drag Reduction Conference held 2000 in Potsdam, Germany, and the CEAS/TRA3 Aerospace Aerodynamics Research Conference held in 2002 in Cambridge, UK – was to present and discuss progress and future needs in key aerodynamic technology areas especially with regard to the goals established and reported by the “Group of Personalities” in “European Aeronautics – a Vision for 2020”. These goals comprise specifically a 50% reduction in perceived aircraft noise, a 50% cut in CO2 and an 80% cut in NOx emissions as well as a major improvement in aircraft operational procedures. This means basically: Build more efficient, safer and environmentally friendly aircraft. Aerodynamics is the most important contributor to achieving the 2020 Vision goals. The Conference was amalgamated with the 2005 RAeS Aerodynamics Research Conference. Introductory Sessions The Conference was divided into 23 sessions, mostly arranged in three parallel sessions, which made it, of course, impossible to cover all adequately in a review. In an introductory session (1) on the challenges of the 2020 Vision, representatives of the EC (Dr. Knörzer), Research (Dr. Szodruch, DLR) and Industry (Dr. Dirks, Airbus), respectively, outlined the general research and development setup within Europe and addressed past accomplishments, present activities and future needs. One common concern was funding. Here, it was stressed that in the light of present quarrels at the EU there might be serious cuts, while, on the other hand about 50% more money for Research is needed. The Industry representative stated that Airbus needs strong support from all involved in aeronautics to stay successful and competitive. There was a general statement that we still seem to be a long way from reaching the goals of the 2020 Vision and that more dramatic novel configurations are needed to reach the set goals. Novel configurations were addressed specifically in Session 2 but also throughout the Conference. Considered were, for instance, a Flying Wing, the configurations of the NEXUS Program, namely a Blended Wing Body (BWB) configuration and a Forward Swept Wing (FSW), unconventional empennages, i.e., a U-tail and a V-tail, respectively, and an Energy Scavenging Wing. Although not so new, except for the Energy Scavenging Wing, these configurations still seem to be “sitting at the onset of their development or operation”. This holds, of course, definitely for the Energy Scavenging Wing – for instance realized by a thin
film sprayed on relevant surfaces, which will transform turbulence energy into a usable form, namely electricity. (Please come back in 30 years.) A special mention deserves the first Plenary Lecture in Session 3 “Boeing 787 Design for Optimal Airplane Performance” since the 787 Airplane and its derivatives seem to realize a 20% improvement in efficiency thus possibly constituting guidance towards achieving the goals of the 2020 Vision. Some of the measures leading to the improvements included:
• Realization of most of the aircraft by employing carbon fiber thus considerably reducing weight.
• Aerodynamic design by extensive use of CFD and verification through specific wind-tunnel tests (e.g., in the ETW at full-scale Reynolds numbers). Still wind-tunnel time was reduced by 30% due to heavy use of CFD.
• Full fly-by-wire aircraft and propulsion by very high by-pass ratio engines. As seen in the above example, rapid computational design and analysis tools play an ever-increasing role not only in aerodynamics but also in considering the complete aircraft. One must combine tools to treat, for instance, aerodynamics, structural mechanics, flight mechanics and propulsion, i.e., perform a “multidisciplinary design”. This was stressed several times during the Conference and named as one ingredient to success in reaching the set objectives. Being here mainly concerned with key aerodynamic issues, the importance of numerical simulation was similarly emphasized throughout the course of the corresponding presentations and most investigations were performed by CFD in conjunction with experiments stressing the inseparability of CFD, experiment and (not necessarily first) physical understanding. Other Major Topics Flow Control Methods and Special Aerodynamic Devices Wide coverage and interest was given to flow control methods and concepts, either applied to specific configurations or studied in basic numerical and experimental investigations; such methods are believed to be one possible way of reaching the desired objectives. Control methods are hence addressed again and again during the course of the Conference. Here, we shall briefly look at the methods or procedures considered following somewhat the order of appearance.
• Pneumatic vortex generator jets were used for high-lift and transonic buffet improvements.
• A synthetic jet through a leading edge slot was similarly employed. • Solid vortex generators upstream of the shock were used to control buffet. • Trailing edge deflectors were employed for the same purpose. • Sub-boundary-layer vortex generators were found to delay transonic buffet onset and
to increase the efficiency of conventional high-lift systems; they can also be used on flaps to suppress separation.
• Pulsed Lasers (non intrusive) allow to excite the flow by heating the surface, e.g., with a short focused pulse, to generate turbulent flow structures.
• Plasma - assisted flow control with the ionized and accelerated air acting as wall jets were addressed.
• Pulsed-jet actuators, for instance generated by MEMS, were shown to prevent separation.
• Boundary layer suction was employed for drag reduction and high-lift improvement. • Surface bumps to reduce wing drag due to shock waves were considered.
Other devices considered – not necessarily control devices in the common sense but still effective in enhancing aircraft performance at reduced complexity – included Wing-tip Devices and mini Trailing Edge Devices (TEDs). The Wing-tip devices investigated included, besides the conventional clean Küchemann tip, for instance, fences and large winglets; also spanwise and normal steady blowing and synthetic jets emanating from the wing tip to affect the wake vortices were studied. Winglets were, in turn, also equipped with leading and trailing edge devices. High-lift Systems and Noise Reduction Special attention was given to efficient innovative high-lift systems since they are the prerequisite for improvements in several of the 2020 Vision goals such as the reduction of perceived noise and CO2 emissions and the increase in start and landing frequencies. In addition, there is a demand for a reduced complexity of the high-lift wing designs, for instance, by introducing slot-less and advanced drooped-nose designs. Of course, flow control also plays a significant role. The importance of high-lift designs is reflected in several national and European projects. Laminar Flow Technology, Transition Prediction and Control Drag reduction is, of course, one of the dominant goals in aeronautics. Laminar flow technology has, therefore, been extensively investigated. It has been demonstrated, for instance, that it is possible to apply Hybrid Laminar Flow Control (HLFC), which seems to be the most promising concept, on an Airbus-size aircraft. The problem to be addressed and solved is, when considering a large wing, to provide a feasible weight-reduced suction system with low energy consumption. The increased complexity and costs might, however, still render an HLFC-aircraft unattractive to a manufacturer or operator. An extension of the concept of HLFC to include micro-blowing in the downstream turbulent boundary layer to further reduce drag, using the air removed upstream, might enhance the attractiveness and should possibly be explored further. Concerning transition control, a new (?) technique, introduced by Bill Saric, is worth mentioning. This technique involves the manipulation of the natural instabilities in the boundary layer using micron-sized roughness elements spaced, for instance, along the attachment line edge of a wing. General Remarks The presentations revealed a large spectrum of extremely interesting activities in key aerodynamic areas which might all (some day) contribute to the goals of the 2020 Vision. There seems to be a considerable amount of dedicated work in progress at Research Institutions, Universities and Industry; the results are promising. The number of European and national programs seems to be quite large which should guarantee a good cooperation between all partners involved. But still, one sometimes has the feeling that many activities – and here especially, but not only, the newer control concepts, for instance, depending on
Synthetic Jets and similar devices – are restricted to Universities and small-scale wind tunnels (good for a Ph.D) but should actually be tested on realistic large-scale air vehicle configurations. Many sessions and individual contributions were also too concerned with the description of tools and procedures rather than detailed results and the benefits with regard to the set goals. It was very positive that the approaches taken by almost all researchers and research groups were to always consider experiments in conjunction with CFD modelling and simulation (or vice versa), one of the necessities in reaching our goals. Also remarkable is the high standard in research and development we have reached in Europe. Generally, there seems to be a lack of integrating all the devices investigated – except possibly for the laminar flow control activities – into demonstrator programs as seems to be the case, e.g., in the AWIATOR program. As was said during the Round Table Discussion: Many concepts that are being investigated may be too late for contributing to the 2020 Vision goals one reason being that we need a closer tie and shorter, organized ways between Research and Application. Most of all, it was said, we need a "Break Through" to meet the 2020 Vision objectives. Where are the Break Throughs? Is it Laminar Flow Technology, weight reduction by composites or a multidisciplinary approach to design. Most likely, we need all. Finally, concerning the concept of the Conference, it seems that such a conference is an excellent – and necessary – way to disseminate and discuss the results of national and European research and to map out and coordinate future activities needed to reach the set objectives. Somewhat detrimental – but understandable – seem to be the parallel sessions since it takes at least two and their exchange to cover all presentation; but there is, of course, still the conference proceedings. The Conference was well organized and the settings and procedures were very adequate. The number, scope and timing of the social events nicely supplemented the serious deliberations of the Conference. Göttingen, July 14, 2005
