Comparison of Open-Source CFD Software for Aerodynamic Analysis of Mini-UAV

Tomas Ba�a ilJniv,ersity in Zlin Facu tv of Applied Informatics

Tomas Vogeltanz Department of Informatics and Artificial Intelligence

Tomas Bata University in ZHn

Czech Republic

17.09.2015

Content

• Free Software • Mini-UAVs • Aerodynamic Analysis

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Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

Introduction Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

• The aerodynamic analysis often plays a major role in the early stage of a design phase.

- Major changes during conceptual phase

- Minor changes after conceptual phase

• Incorrect analysis => loss of money • Suitable aerodynamic behavior is necessary. • Two options:

- Wind tunnel test

- CFD analysis

3

Free Software

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Figure 1. Free Software Connections

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Free Software - Design & Mesh Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

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• OpenVSP is a parametric and easy­to-use aircraft geometry application.

• AirfoilTools generates the Selig and Lednicer airfoil OAT files.

• enGrid is an open-source mesh generation application.

• Larosterna is a design tool with an option to import a SU2 mesh file.

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Free Software - CFD

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Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

• The Stanford University Unstructured (SU2) suite solves complex, multi­physics analysis and optimization tasks using arbitrary unstructured meshes.

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Free Software - CFD

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Figure 3. CFD Software

Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

• The Open Field Operation and Manipulation (OpenFOAM) CFD Toolbox includes:

- over 80 solver applications

- over 170 utility applications for pre- and post-processing tasks

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Free Software - CFD

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Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

• Code_Saturne is based on a Finite Volume Method which accepts 3D meshes built with

- any type of cell (tetrahedral, hexahedral, prismatic, pyramidal, and polyhedral)

- any type of grid structure (unstructured, block structured, hybrid)

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Mini-UAVs

• Common parameters of mini-UAVs:

- Wingspan < 6 m

- Weight < 25 kg

- Low speeds (between 20 and 120 km/h)

- Low altitudes (from 3 to 1000 m)

• Primary Requirements:

- Long flight duration - All-weather capabilities

- Success in missions

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Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

SAGITTA

Figure 4. SAGITTA UCAV Concept [1]

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Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

SAGITTA

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Figure 5. Wing Planform of SAGITTA Demonstrator [2]

• Symmetrical airfoil - NACA64A012

1 1

Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

AVIGLE

Figure 6. Wind Tunnel Model of AVIGLE UAV [3]

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Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

AVIGLE

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Aerodynamic Analysis Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

• 2 mini-UAVs analyzed in 3 CFD applications

- SU2

• ROE (Roe's Approximate Riemann Solver) • JST (Jameson-Schmidt-Turkel)

- OpenFOAM

- Code Saturne

• Results

- SAGITTA with Boundary Layer

- AVIGLE without Boundary Layer (enGrid crashed)

- SAGITTA without Boundary Layer (for comparison)

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Aerodynamic Analysis - SAGITTA - Lift Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

Figure 8. SAGITTA Demonstrator - CL VS. a

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Aerodynamic Analysis - SAGITTA - Drag

Figure 9. SAGITTA Demonstrator - CO VS. a

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Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

Aerodynamic Analysis - SAGITTA - Lift/Drag Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

Figure 10. SAGITTA Demonstrator - CL/Co vs. a

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Aerodynamic Analysis - AVIGLE - Lift Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

Figure 11. AVIGLE Tiltwing UAV - CL vs. a

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Aerodynamic Analysis - AVIGLE - Drag Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

Figure 12. AVIGLE Tiltwing UAV - Co vs. a

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Aerodynamic Analysis - AVIGLE - Lift/Drag Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

Figure 13. AVIGLE Tiltwing UAV - CL/CD VS. a

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SAGITTA with and without Boundary Layer - Lift Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

Figure 14. SAGITTA Demonstrator with and without Boundary Layer - CL vs. a

2 1

SAGITTA with and without Boundary Layer - Drag Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

Figure 15. SAGITTA Demonstrator with and without Boundary Layer - CD vs. a

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SAGITTA with and without Boundary Layer - Lift/Drag Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

Figure 16. SAGITTA Demonstrator with and without Boundary Layer - CL/Co vs. a

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Discussion and Conclusion

• CFD results depend on:

- Software/Developers

- Mesh quality of UAV model

- Modeler

• Wind-tunnel results depend on:

- Wind tunnel

- Measuring instruments

- Manufacturing quality of UAV model

- Human factor

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Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

Discussion and Conclusion Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

• Open-source CFD software with an appropriate setting and mesh may accurately compute lift and drag coefficients.

• Time vs. Money & Repeatability • Similar results from OpenFOAM and Code_Saturne • SU2

- JST - symmetrical UAVs (or wings) with higher Reynolds number (1.7e6)

- ROE - asymmetrical UAVs with lower Reynolds number (2.82e5)

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Summary

• Free software

Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

• 2 mini-UAVs analyzed in 3 CFD applications

- SU2

• ROE (Roe's Approximate Riemann Solver) • JST (Jameson-Schmidt-Turkel)

- OpenFOAM

- Code Saturne

• Results

- SAGITTA with and without Boundary Layer

- AVIGLE without Boundary Layer

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Future Work Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

• 3D-printed models -> wind-tunnel tests • Printed model � computer model • => more precise and objective CFD evaluation • Results

- PyFR

- HiFiLES

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References Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

[1] SAGITTA, June 10, 2015, http://www.unibw.de/lrt13 2/Forschung/Projekte/SAGITTA.

[2] H6velmann, A., C. Breitsamter, 2012, Aerodynamic Characteristic of the SAGITTA Diamond Wing Demonstrator, Deutscher Luft- und Raumfahrtkongress, 14 p.

[3] Holsten, J., T. Ostermann, D. Moormann, 2011, Design and wind tunnel tests of a tiltwing UAV, CEAS Aeronautical Journal, vol. 2, no. 1-4, pp. 69-79.

[4] AVIGLE, June 22,2012, http://www.fsd.rwth-aachen.de/English/Research/Avigle.php

[5] McCormick, Daniel J., May 27,2002, An Analysis of Using CFD in Conceptual Aircraft Design, Blacksburg, Virginia, USA, Faculty of Virginia Polytechnic Institute and State University, 152 p.

[6] Mueller, T. J., J. D. DeLaurier, 2003, Aerodynamics of small vehicles, Annu. Rev.

Fluid Mech, vol. 35, no. 1, pp. 89-111,001: 10.1146/annurev.fluid.35.101101.161102.

[7] Vogeltanz, Tomas, 2015 (03/22), A Survey of Free Software for the Design, Analysis, Modelling, and Simulation of an Unmanned Aerial Vehicle, Archives of Computational

Methods in Engineering, 66 p., 001: 10.1007/s11831-015-9147-y.

[8] OpenVSP, August 19, 2015, http://openvsp.org/.

[9] AirfoilTools, 2015, http://airfoiltools.com/.

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References Tomas Balal Univ,ersity in ZlIn Faculty of Applied Informatks

[10] enGrid - open-source mesh generation, 2012, http://engits.eu/en/engrid.

[11] Eller, D., Larosterna: about, 2014, http://www.larosterna.com/index.html.

[12] SU2: The Open-Source CFD Code, August 27,2015, https://github.com/su2code/SU2/wiki.

[13] OpenFOAM Foundation, OpenFOAM, 2015, http://www.openfoam.org/index.php.

[14] ENGYS Ltd, HELYX-OS: Engys' free-to-download Open Source native GUI for OPEN FOAM®, 2015, http://engys.com/products/helyx-os.

[15] EDF R&D, Welcome to Code_Saturne, 2015, http://code-saturne.org/cms/.

[16] Jin, Wonjin, Yung-Gyo Lee, 2014, Computational Analysis of the Aerodynamic Performance of a Long-Endurance UAV, International Journal of Aeronautical and Space

Sciences, vol. 15, no. 4, pp. 374-382,001: 10.5139/IJASS.2014.15.4.374 ..

[17] Uragun, S., December 18-21,2011, Energy efficiency for unmanned aerial vehicles, 2011 10th International Conference on Machine Learning and Applications, Honolulu, Hawaii, USA, pp. 316-320,001: 10.1109/ICMLA.2011.159.

[18] McAlpine, J.D., Computational Fluid Dynamics or Wind Tunnel Modeling?, 5 p., www.envirometrics.com/abstracts/CFDvsWlpdf.

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Thank you for your attention

Tomas Ba�a ilJniv,ersity in Zlin Facu tv of Applied Informatics

Do you have any question?

vogeltanz@fai.utb.cz