Computational fluid dynamics (CFD) is a powerful tool to simulate, analyze, and optimize designs. The leading CFD providers will discuss software features and functionality such as flow features and benefits, solver technology, as well as describe an example of CFD use in the real world.

1. Computational Fluid Dynamics
-Key Features & Best Practices

2. Before We Start
This webinar will be available afterwards at
www.designworldonline.com
Q&A at the end of the presentation
Hashtag for this webinar: #CFDweb

3. Moderator
Laura Carrabine
Design World
Presenters
David Kan
Wim Slagter
Ivo Weinhold
COMSOL
ANSYS
Mentor Graphics
Derrek Cooper
Autodesk

4. Courtesy of Borg Warner Turbo & Emissions Systems
Wim Slagter
Lead Product Manager, ANSYS, Inc.
Courtesy of CADFEM Russia
Computation Fluid Dynamics –
ANSYS Software Key Features
and Best Practices

5. ANSYS, the company
• ANSYS design, develops, markets
and globally supports a
comprehensive range of
engineering simulation software
• Proven software technologies for
o Fluid Dynamics
o Structural Mechanics
o Acoustics
o Electromagnetics
o Multiphysics
• Specialized tools, incl.
o ANSYS Icepak (thermal/flow
for electronics)
o ANSYS nCode DesignLife (for
fatigue)
• World’s largest pool of experts
providing CFD Best Practices
Design
Exploration
Parametric
Simulation
Emag
Structural
Fluid
CAD
Import
Acoustics
Postprocessing
Meshing

6. ANSYS – addressing your current & future CFD challenges
Transient or steady-state
Heat transfer
Laminar and turbulent flows
Moving geometry and mesh
Buoyant flows
Rotating machinery
Solution-based adaptive remeshing
Incompressible / compressible
Real gas modeling
Multi-component flows, multi-phase
Courtesy of BMW AG
Reactions and combustion
Filters/porous regions
1-way and 2-way Fluid-Structure Interaction
Courtesy of GE Energy

7. Engineering Productivity: Geometry Modeling
Key Enablers:
• Links to almost any CAD system
• Parametric, persistent process
• Simulation focused: allows
engineers to do simulation driven
product development
CAD Neutral: Direct and
• Direct modeling allows for reFeature-Based Modeling!
animating dumb CAD (geometry
without parameters) models
• Extensive modeling solutions
Bi-directional CAD connections
Feature-Based Modeling
Direct Modeling

8. Engineering Productivity: Workflow
Geometry
Meshing
Problem Setup
Setup Wizards
Customized Menus
Post Processing
Increased Productivity through
Automation and Customization!

9. Engineering Productivity: Accuracy & Speed
• Advanced physical models
• High-performance solvers
Free surface profiles
• Steady-state scheme
• Transient scheme
• Experiment
RANS
New
Get reliable steady-state scheme as accurate as transient Wigley hull simulation
answers faster,
Re=395
User-defined LES for highest accuracy;
without compromise on flow physics!
LES
RANS for all other areas
Head rise coefficient
1.0
Hofmann et al [20]
CFD
0.9
0.8
0.7
0.6
0.5
0.4
0.0
0.5
1.0
1.5
Cavitation number
Cavitating flow in a centrifugal pump can also be modeled in steady state
Recondisation simulation

10. Integrated Design Exploration & Optimization
Parametric CAD model
Effective Flow Area
Guide
Curve
Radius
Guide
Curve
Angle
Section
Length
Section Length
Response Surface and Sensitivity Chart
Gain deep insights necessary to
optimize product performance, and
produce better products faster!
Baseline Design
Optimized Design
Tradeoff Chart
Guide Curve
Angle
(Deg)
Guide Curve
Radius
(mm)
Section
Length
(mm)
EFA
(mm2)
Baseline
63
41
51
1100.2
Optimized
50
30
60.5
1180.4
DOE generated with Design Points

11. Shape Sensitivities wrt Design Variables
Adjoint flow solver:
• An understanding of the shape sensitivities with respect to design variables
in a single computation!
• A quantitative performance estimate due to a design change without the
need to simulate the actual change!
Adjoint is a very efficient Total pressure drop sensitivity
means of
quickly exploring a design space with
thousands degrees of design freedom!
Drag sensitivity
Estimated downforce improvement = 41.6N
Actual downforce improvement = 39.1N
Downforce sensitivity
Total pressure drop sensitivity

12. Fluid-Structure Interaction
Rigid Body FSI
1-way FSI
2-way FSI
Fluid Flow
Comprehensive suite of FSI
capabilities for accurate prediction of
a broad range of design scenarios
Deformation
Courtesy of Embraco
Thermal Stress

13. Customer Example: Dyson Air Multiplier™ Fan
• Design objective:
o Maximize amplification ratio for a given size and power consumption
o 3 main design parameters, i.e. gap in annular ring, internal profile of ring,
profile of external ramp
• Customer benefits include:
o Explored 10-fold of design variations than would otherwise have been
possible (each day 10 instead of 1)
o Improved performance 250% over original design
Courtesy of Dyson

14. Customer Example: Exhaust Manifold
• Design objective:
o To optimize the dual-outlet exhaust manifold for robust performance
o 4 main design parameters, i.e. outlet diameter of the manifold, thickness
at inlet, external temperature, engine RPM
• Design constraint:
o Maximum displacement should not exceed 1.5 mm!
Temperature
Deformation
Effect of engine speed and thickness at outlet on
maximum deformation
Fluid Flow
All samples report maximum deformation
below 1.5 mm
Von Mises Stress

15. THANK YOU!
www.ansys.com

16. Enabling engineers to get more done
in 24 hours than any other methoddigital or physical!
Derrek Cooper
Product Manager
Autodesk

17. Background
• Blue Ridge Numerics, Inc.
• Founded in 1992
• Flagship Product = CFdesign
• Leader in upfront CFD

18. upfront CFD: Fastest way to solving flow & thermal design challenges!
Enabling Technologies
CAD
Groups
MCAD
Connections
Templates
Materials
Rules
Configurations
iAssys
Instances
Associativity

19. upfront CFD: Fastest way to solving flow & thermal design challenges!
Enabling Technologies
Intelligent
Automatic
Meshing

20. upfront CFD: Fastest way to solving flow & thermal design challenges!
Enabling Technologies
Geometry
Mesh
Diagnostics
Intelligent
Automatic
Meshing
Automatic
Mesh Sizing
Mesh
Refinement
Regions
Automatic
Boundary
Layer Meshing
Extrusion
Meshing
Automatic
Gap
Refinement
Powerful
Advanced
Tools

21. Solver Technology
Accurate
FAST
AccelerantTM
Finite Element
Solver
Krylov
sparse matrix
solver
Intelligent
Solution
Control
Auto
Convergence
Assesment

22. Enabling Technologies
What If!
Unified
Design Study
Environment
Cloning
Critical
Values
Design
Review
Center
Pass/Fail
Summary
Data

23. Case Study
Lighting manufactures moving to
LEDs due to longer life & better
performance
Challenge- Temperatures must
remain lower than traditional
lighting
The cooler it is, the longer it lasts
Rule of thumb – airflow is as
important as surface area

24. Case Study

25. upfront CFD: Fastest way to solving flow & thermal design challenges!
CFdesign = upfront CFD
Intelligent
Automatic
Meshing
MCAD
Connections
AccelerantTM
Finite Element
Solver
Unified
Design Study
Environment

26. Thank you…

27. David Kan

28. CFD in COMSOL—Principles
•
Ease-of-use
o Tailored functionality and
interfaces
o Robust
•
Efficiency
o State-of-the-art performance
o Accurate
•
Multiphysics
o Fluid flow with any physics
combination
Fluid flow past a solar panel


f  n  pI   u  u
T


29. CFD in COMSOL—Technology
•
Finite Element Method
•
Accuracy
•
Stability
•
Meshing
•
Compatibility

30. CFD in COMSOL—Applications
Reactor with free
and porous flow
regions
Inkjet
Journal bearing

31. CFD in COMSOL—Results
Gianluca Argentini of Riello Burners in Legnago, Italy

32. Thank you!

33. FloEFD
Concurrent CFD Embedded
in the Design Process
Dr. Ivo Weinhold
Mentor Graphics Corporation
Mechanical Analysis Division
© Mentor Graphics Corp. 2011 – v2.0

34. Physical Modeling: Advanced Radiation Model
Advanced Radiation Model
• Radiation is one of the three fundamental methods of heat transfer
• A radiation model must consider the complex physics involved in
radiative heat transfer
• Correct radiation simulation is essential for the correct prediction of
the temperature distribution in many designs
• Radiation plays an important role for simulations of fluid flow and
heat transfer in automotive, building design, electronics cooling, and
many more

35. Physical Modeling: Advanced Radiation Model
Advanced Radiation Model
• Radiation absorption in
solids
• Wavelength dependency
• Spectrum definition
• Specularity of surfaces
• Refractive index

36. Physical Modeling: Cavitation Model
Cavitation Model
• Cavitation describes the process of vaporisation, bubble generation
and bubble implosion in a flowing liquid as a result of a decrease and
subsequent increase in pressure if the pressure declines to some
point below the saturated vapor pressure of the liquid.
• It can occur in control valves, pumps, propellers, impellers, etc.
• The shock waves formed by cavitation are strong enough to
significantly damage moving parts. Therefore cavitation is usually an
undesired effect.
• Cavitation is a major field in the study of fluid dynamics.
Source: Wikipedia

37. Physical Modeling: Cavitation Model
Cavitation Model
FloEFD includes two cavitation modeling approaches:
• Engineering cavitation model (for water only):
• This model employs a homogeneous equilibrium approach
and has the capability to account for thermal effects.
• Isothermal cavitation model:
• This model is based on the approach considering isothermal
two-phase flows for user-defined incompressible liquids.
Reference: Wesley, H. B., and Spyros, A. K.: Experimental and computational investigation of
sheet cavitation on a hydrofoil. Presented at the 2nd Joint ASME/JSME Fluid
Engineering Conference & ASME/EALA 6th International Conference on Laser
Anemometry. The Westin Resort, Hilton Head Island, SC, USA August 13 - 18, 1995

38. Solver Technology: Numerical Schemes
Numerical Schemes
• Cell centered finite volume method
• Unified implicit method for both incompressible
and compressible liquids and slightly compressible gas
flows; Explicit method for high Mach number flows
• Coupled solver for momentum equations
• Conjugate formulation for heat transfer calculation
in fluid and solid
• Second order scheme for approximation of
conservation laws in fluid and solid
• Monotonic scheme for incompressible tasks
• Multigrid method for linear algebra solver
• CPU time per cell and iteration is independent from
cell count

39. Solver Technology: Mesh Generation
Mesh Generation
• Automatic meshing of fluid and solid regions
• Immersed Boundary Cartesian mesh technology
• Automatic mesh refinement/unrefinement due
to geometrical and/or physical (solution adaptive)
requirements
• Special cost-effective treatment of thin solids and
thin channels
• Automatic immersed boundary treatment
(near-wall physics)

40. Customer Example: AEG Electric Tools – Angle Grinder
AEG Electric Tools - Angle Grinder

41. Customer Example: AEG Electric Tools – Angle Grinder
Design Challenge:
• Optimize housing openings for cooling performance, dust protection
and safety requirements
Benefits:
• The new design protects the motors from abrasive dust while the
optimized airflow prevents dust accumulation in sensitive areas such
as the switch and electronics.
• It guarantees a better cooling effect – all of which lead to an up to
10 times longer tool lifetime than competitive angle grinders with
metal dust chambers.

42. www.mentor.com

43. Questions?
Design World
Laura Carrabine
lcarrabine@wtwhmedia.com
@wtwh_laurac
ANSYS
Wim Slagter
wim.slagter@ansys.com
Mentor Graphics
Ivo Weinhold
ivo_weinhold@mentor.com
COMSOL
David Kan
david.kan@comsol.com
Phone: 310.441.4800
Autodesk
Derrek Cooper
derrek.cooper@autodesk.com
Phone: 215.717.7265
Twitter: @derrekcooper
LinkedIn: .../in/derrekcooper

44. Thank You
 This webinar will be available at
www.designworldonline.com & email
Tweet with hashtag #CFDweb
Connect with
 Twitter: @Design_World
 Facebook: /engineeringexchange
 LinkedIn: Design World Group
Discuss this on EngineeringExchange.com