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CFD at volvo car corporation
Johan Ljungberg
jljungb3@volvocars.com
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 2
AGENDA
…..
What/Why CFD? History
Process overview
CFD attributes
Introduction
CFD Process
…..
….. CFD activities at VCC
….. Daily use of CFD Cfd AERODYNAMICS
….. Remote simulation Cfd web
2
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 3
What is cfd?
COMPUTIONAL FLUID DYNAMICS - The analysis of fluid flow, heat transfer and other related phenomena with aid of
advanced numerical techniques, softwares and computers
Why cfd?
UNDERSTANDING the complete picture of the flow at anytime
Meets the need for REDUCED LEAD TIME
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 4Page 4Issue date: 2010-04-19, Security Class: Public
1990: Basically 2D computations
1991: 1:st 3D external flow computation
(100000 cells)
Lead time 3 to 4 months
1993: CFD used in the early stages
of car development
Lead time 6 weeks
2000: Focus on model complexity
Lead time 8 weeks
2010: Detailed floor calculation
(60 millon cells)
Lead time 4 weeks
(2 days / configuration)
History of the cfd group at volvo cars
3
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 5Page 5
CAE GRoups at volvo cars
Computional fluid dynamics
Powertrain, combustion systems
Saftey and crash
Durability and nvh
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 6Page 6
CFD attributes
CLimate
thermodynamics
contamination
aeroacoustics
4
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 7
SERVER – 660 CPU:s
PCVISTA (64 bits), 32-98 GB, Multi processors
Used for pre- and
post-processing
Used for the Solver
Cfd process
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 8
3) Simplied
CFD process
Tce – cad extraction
5
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 9
CFD process
Tce – cad extraction
Wraping – Complex geometry treatment
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 10
CFD process
Tce – cad extraction
Wraping – Complex geometry treatment
Ansa – model preparation
6
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 11
CFD process
Tce – cad extraction
wraping
Ansa – model preparation
Harpoon – Volume mesh
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 12
CFD process
Tce – cad extraction
Wraping – Complex geometry treatment
Ansa – model preparation
Harpoon – Volume mesh
Fluent - solver
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2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 13
Harpoon – Volume mesh
Ansa – model preparation
Wraping – Complex geometry treatment
CFD process
Tce – cad extraction
Fluent - solver
Ensight – post processing
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 14
CFD aerodynamicsClosed front / semi detailed
Closed front, i.e
no cooling flow
Symmetrycondition
Open front / fully detailed
Detailed enginecompartment
None symetric
8
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 15
CFD aerodynamics
Exterior optimization: closed front
Late separation Good separation
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 16
CFD aerodynamics
Exterior optimization: closed front
Iso surface total pressure
Velocity plane 100mm downstream base
Skin friction
9
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 17
CFD aerodynamics
Exterior optimization: open front
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 18
CFD aerodynamics
CD vs xDrag per part
Force (N) Cd*A Cd %
Exterior 153,9 0,331 0,143 48,5
Front Wheels 23,6 0,051 0,022 7,5
Rear Wheels 16,4 0,035 0,015 5,2
Front Suspension 7,1 0,015 0,007 2,2
Rear Suspension 8,7 0,019 0,008 2,8
Front Wheel Deflectors 8,1 0,018 0,008 2,6
Cooling Package 97,3 0,209 0,090 30,7
Drive line 64,2 0,138 0,060 20,3
Floor -62,4 -0,134 -0,058 -19,7
TOTAL 317,25 0,682 0,295 100,0
Force (N) Cd*A Cd %
Exterior 153,9 0,331 0,143 48,5
Front Wheels 23,6 0,051 0,022 7,5
Rear Wheels 16,4 0,035 0,015 5,2
Front Suspension 7,1 0,015 0,007 2,2
Rear Suspension 8,7 0,019 0,008 2,8
Front Wheel Deflectors 8,1 0,018 0,008 2,6
Cooling Package 97,3 0,209 0,090 30,7
Drive line 64,2 0,138 0,060 20,3
Floor -62,4 -0,134 -0,058 -19,7
TOTAL 317,25 0,682 0,295 100,0
10
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 19
CFD aerodynamics
Morphing
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 20
CFD webConcept Design Aerodynamics by Remote Simulation
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2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 21
CFD webConcept Design Aerodynamics by Remote Simulation
Harpoon (volume mesh)
Fluent (solver) Ensight (pictures)
Ansa (surface mesh)
Process excecuted in batch (by script)
2012-04-23
Johan Ljungbergjljungb3@volvocars.com
CFD @ VCC
Page 22
Research topicsWheels and wheelhouses: MSc. and Ph.D
~ 8 mm
(250 Km/h)
~ 8 mm(250 Km/h)
-0.500
-0.400
-0.300
-0.200
-0.100
0.000
0.100
0.200
0.300
0.400
0.500
0.600
Outer
coverage
factor 1
Outer
coverage
factor 2
Spoke
factor 1
Spoke
factor 2
Spoke
factor 3
Regression model coefficients
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