ANSYS Applications in Ocean Science and Engineering

© 2011 ANSYS, Inc. August 12, 20111

ANSYS Applications in Ocean

Science and Engineering

Marsall Loewenstein

Ian Lockley

8/10/2011


Perspective

The Universe in One Year concept was inspired by the

late Cornell astronomer, Carl Sagan. Sagan was the first

person to explain the history of the universe in one

year—as a “Cosmic Calendar”—in his television series,

Cosmos


Perspective


1769

Benjamin Franklin’s first scientific study of the Gulf Stream. He measured

water temperatures during several Atlantic crossings and effectively

explained the phenomena.

11:59:59.5 seconds….

0.5 Seconds of Oceanographic History



1769

Benjamin Franklins first scientific study of the Gulf Stream. He measured

the water temperatures during several Atlantic crossings and effectively

explained tbe phenomena

1855

Physical Geography of the Sea, by Matthew Fontaine Maury published in

1855 was the first textbook of Oceanography.

0.5 Seconds of Oceanographic History

11:59:59.5 seconds….


Relevance to Science / Engineering / Product Design

• The pace of academic endeavors, discovery and information continues to

grow at an exponential rate

• Scientists and Engineers are constantly challenged or asked to do more

with less

• Time and expense of developing industrial and research equipment test

must be reduced

• Quality and safety must continue to rise

• We must all be stewards of our precious environment

• “Cut and try” approaches in science and engineering must be

supplemented or replaced with simulation

• Many mature software tools exist from ANSYS, across an

enormous range of physical disciplines, which enable

research and the development and testing of both concepts

and products through physics based numerical simulation


• Brief Introduction to ANSYS

• Selected Simulation Applications

– Environmental

– Pollution dispersion, cleanup, scouring,

ocean currents, noise …

– Energy

– Wave energy, tidal energy, energy

environmental impact

– Marine

– Hull design, propulsion, system design,

sensor design ….

Overview




– Environmental



– Energy



– Marine


sensor design ….

Overview

© 2011 ANSYS, Inc. August 12, 201110

FocusedThis is all we do: Physics based software simulation tools for

science and engineering

Capable2,000 employees

60 locations, 40 countries

Trusted96 of top 100 FORTUNE 500 industrials

ProvenRecognized as one of the world’s most innovative

and fastest-growing companies*

A 40 year track record of innovation

IndependentLong-term financial stability

CAD agnostic

*BusinessWeek, FORTUNE

(image of engineer working through simulation problem)

Who is ANSYS

© 2011 ANSYS, Inc. August 12, 201111

In-house

Solution

One Picture of ANSYS

Structural

Fluids

Thermal

Emag

CAD

Import

Param-

terizationMeshing

Workflow

Post-

processing

PlantD(s)

y(t)u(t)+

-

ANSYS is the leading provider of

physics based engineering

software tools

• Structural

• Thermal

• Electromagnetics

and

• Fluids

© 2011 ANSYS, Inc. August 12, 201112

Industry Leading Customers

© 2011 ANSYS, Inc. August 12, 201113

Selected Academic Customers

© 2011 ANSYS, Inc. August 12, 201114

“By embedding ANSYS technology in our engineering curriculum, Cornell is producing

students who can go into industry with a strong foundation in the application of

advanced simulation.”

Professor Rajesh Bhaskaran

Cornell University

ANSYS Academic Program

Presence

• Academic products used at 2,400 institutions

worldwide, with nearly 87,000 licensed seats

Value to Industry

• Students trained in ANSYS join industry with

experience in simulation

• Research use of ANSYS helps tackle next-generation

industry challenges

Software Technology

• Academic partnerships ensure our product

technology leadership

Dr. Rajesh Bhaskaran

Cornell University

ANSYS Academic Program

© 2011 ANSYS, Inc. August 12, 201115

Typical Marine CFD Applications

• Hydrodynamics

• Ship hulls

• Submarines

• Yacht hulls, keels

• Appendages

• Other underwater systems

• Towed sonar arrays

• Propulsion

• Propeller / Hull interactions

• Water jets

• Cavitation

• Bubble wakes and signature

• Acoustics

• Aerodynamics

• Superstructures

• Dispersion

• Yacht Sails

• Exhaust plumes

• Ventilation

• Heli Deck operations

• Fire Suppression

• Halon replacement

• Blast interactions

• Fluid Structure Interaction

• Floating objects

• Flexible objects

• Vortex Induced Vibration

• Swim suits

• Heat transfer• Fuel Cells

• Wave slam

• Flooding in Ro-Ro ferries

• Cavitation

• Torpedoes

• Sloshing in tanks

• Submarine Reactors

• Structural vibrations

• Periscope / free surfaces

• Pumps• Offshore Power

generation

• Chemical reactions• Free surface flows• Microfluidics• Hypersonics• CVD

© 2011 ANSYS, Inc. August 12, 201116



– Environmental



– Energy



– Marine


sensor design ….

Overview

© 2011 ANSYS, Inc. August 12, 201117

© 2011 ANSYS, Inc. August 12, 201118



– Environmental



– Energy



– Marine


sensor design ….

Overview

© 2011 ANSYS, Inc. August 12, 201119

Environmental: Scouring

© 2011 ANSYS, Inc. August 12, 201120

Scouring: Challenges

© 2011 ANSYS, Inc. August 12, 201121

Scouring: Examples

© 2011 ANSYS, Inc. August 12, 201122

CFD modeling of scour around offshore wind turbines in areas with strong currents, Solberg et al, Conference on Offshore Wind Turbines Situated in Strong Sea Currents, 2006

© 2011 ANSYS, Inc. August 12, 201123

Advanced numerical modeling of the scouring process around the piers of a bridge, Motta et al, Proc of the congress, IAHR, 2007

© 2011 ANSYS, Inc. August 12, 201124

Illustration Problem

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Modeling Approach

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Initial Results

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Numerical simulation of scour around pipelines using an Euler-Euler coupled two-phase model, Zhao and Fernando, Environmental Fluid Mechanics, (2007)

© 2011 ANSYS, Inc. August 12, 201128

Environmental: Oil Spill and Cleanup

© 2011 ANSYS, Inc. August 12, 201129

Environmental: Oil Spill and Cleanup

© 2011 ANSYS, Inc. August 12, 201130

CFD Modeling of Oil Spill

Past CFD studies employed VOF approach to study oil spill

• Free surface was captured by VOF

• Linear wave profiles was used to describe wave boundary condition

• Studies were limited to 2D

• Studies were conducted for different wavelength and amplitude

30

© 2011 ANSYS, Inc. August 12, 201131

Current CFD Model

Full 3-dimensional Model

Volume of Fluid (VOF) – Approach• A single set of momentum equations is solved and the volume

fraction of each immiscible phase is tracked

• Three phases – Air, Water and Oil is considered

Open channel wave boundary condition -used

to prescribe wave motion

A fifth order stokes wave theory is used to

describe a non-linear wave

Turbulence – Realizable k-ε model

31

© 2011 ANSYS, Inc. August 12, 201132

3D CFD Model

32

2 KmOpen Channel

Boundary Inlet

Oil Inlet

Open Channel

Pressure Outlet

Top Surface - Outlet

Oil Spill Location

Around 565,000 Grid Elements Used

Grid refined near sea surface to capture waves

© 2011 ANSYS, Inc. August 12, 201133

Wave Profiles

33

5m Amplitude and 500m Wavelength Wave



© 2011 ANSYS, Inc. August 12, 201134

Wave Profile - Animation

34

5m amplitude and 500m Wavelength wave

© 2011 ANSYS, Inc. August 12, 201135

Wave Velocity Profiles

35




© 2011 ANSYS, Inc. August 12, 201136

Observations - Velocity Profiles

High velocity near surface due to waves

As wave steepness increase – Non linear waves results

Coastal region or Shallow water region impacts the wave profile

36

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Oil Slick at Sea Surface

37

5m Amplitude and 500m

Wavelength Wave


Wavelength Wave


Wavelength Wave

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Time History of Spread

38

5m amplitude and 500m Wavelength wave 10m amplitude and 500m Wavelength wave

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39


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40


0.1m/s - Wave Current

© 2011 ANSYS, Inc. August 12, 201141

Observations

Spread pattern is different for different wave

conditions

Polluted area increases with higher interaction

of wave and current

Polluted area is more towards coastal area or in

shallow water

High wave amplitude – oil traveled faster to the

coastal area – thus not spreading

41

© 2011 ANSYS, Inc. August 12, 201142

Conclusions

Overview of the oil spill and its impact on oil and gas

industry

Physics of oil spill – Hydrodynamics of Ocean waves

plays major role

Focused on shallow water waves – Dispersion of oil

slick is more

Need higher order wave theories as wave steepness

increase

42

© 2011 ANSYS, Inc. August 12, 201143

Conclusions

Presented a detailed 3D CFD based model for

study of oil spill• Volume of Fluid (VOF)

• Open channel wave boundary condition

Spread pattern is different for different wave

conditions

Polluted area increases with higher interaction

of wave and current

Value of using CFD based simulations for oil spill

scenarios43

© 2011 ANSYS, Inc. August 12, 201144

Environmental/Marine: Noise

© 2011 ANSYS, Inc. August 12, 201145


MENCK hydraulic hammer

© 2011 ANSYS, Inc. August 12, 201146


Comparison of measured and calculated underwater sound pressure at

a distance of 245 meters from the pile. Knowing the sound propagation

law for this region, the sound pressure at 750 meters can be calculated

and converted into decibels (dB).

© 2011 ANSYS, Inc. August 12, 201147


Underwater sound generation and propagation

shown as a sequence of snapshots in time.

Within a steel pile, the speed of sound is about

5,000 meters per second, while the speed of

sound in water is about 1,500 meters per

second — resulting in radiation patterns and

specific inclination angle.

21

5

43

6

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– Environmental



– Energy



– Marine


sensor design ….

Overview

© 2011 ANSYS, Inc. August 12, 201149

Energy: Wave Energy

© 2011 ANSYS, Inc. August 12, 201150

Energy: Wave Energy

COLUMBIA POWER’s wave power system: The wings and vertical spar

react to the shape of the passing ocean swell. Each wing is coupled by a

drive shaft to turn its own rotary generator.

Wave direction

1 2 3

4 5

© 2011 ANSYS, Inc. August 12, 201151

Energy: Wave Energy

COLUMBIA POWER engineers doubled

efficiency of the buoy by using ANSYS AQWA to

optimize its geometry.

© 2011 ANSYS, Inc. August 12, 201152

Energy: Wave Energy

Maxwell computational

electromagnetics software

from ANSYS was used to

optimize the generator

design.

© 2011 ANSYS, Inc. August 12, 201153



– Environmental



– Energy



– Marine


sensor design ….

Overview

© 2011 ANSYS, Inc. August 12, 201154

Contours of pressure coefficient for the XF5 (left) and the new Kamewa CP-A (right). Insets: Photographs of the blade indicating the locations of the

simulation where cavitation is present (noticeable as pitting). ANSYS FLUENT results helped reduce pressure at the blade root in the CP-A design, indicated

by the lack of cavitation erosion present in the CP-A photo.

Rolls-Royce uses simulation for propeller design to reduce

marine fuel consumption.

According to a 2003 study from the University of Delaware, international

commercial and military shipping fleets consume approximately 289 million

metric tons of petroleum per year, which is more than twice the consumption of

the entire population of Germany. The ANSYS FLUENT simulations run on the

modified propeller geometry predicted that the efficiency would increase by 1

percent to 1.5 percent, and physical experiments confirmed that this was, in

fact, the case.

The new Kamewa

CP-A propeller

from Rolls-Royce

Marine

Propulsion Systems

© 2011 ANSYS, Inc. August 12, 201155

Propulsion Systems

Courtesy SVA-Potsdam (Potsdam Model Basin)

Cavitation Effects

For water pumps, marine propellers, and other

equipment involving hydrofoils, cavitation can cause

problems such as vibration, increased hydrodynamic

drag, pressure pulsation, noise, and erosion on solid

surfaces. Most of these problems are related to the

transient behaviour of cavitation structures. To better

understand these phenomena, unsteady 3D simulations

of cavitating flow around single hydrofoils are often

performed and the results are compared to experiments

Unsteady propeller cavitation in the wake of a ship

© 2011 ANSYS, Inc. August 12, 201156

Propulsion (including Cavitation)

Cavitating Flow Over a Hydrofoil

Cavitating flow over a cambered two-dimensional wing

section was simulated using ANSYS Fluent CFD solver. The

flow angle over the NACA 66 (MOD) hydrofoil is chosen to

represent conditions that are common in water pump and

marine propeller applications. Excellent agreement with

experimental data is obtained for mid-chord cavitation, and

satisfactory agreement is obtained at the trailing edge of the

cavitation region.

Pressure coefficient as a function of normalized chord length

showing ANSYS Fluent results compared with experimental data

Contours of vapour volume fraction show cavitation in the mid-chord region

© 2011 ANSYS, Inc. August 12, 201157

Marine: Sensor Design

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© 2011 ANSYS, Inc. August 12, 201161

Conclusions

ANSYS offers a broad and technically deep set of

physics based research and engineering

software tools which foster understanding,

innovation as well as save time and money

ANSYS is a strong partner for both academic and

industrial organizations seeking such goals

© 2011 ANSYS, Inc. August 12, 201162

Thanks You!

Questions?

[email protected]

[email protected]

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ANSYS Applications in Ocean Science and Engineering

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