ICMMES-2004-68
-
Upload
norbert-gruen -
Category
Documents
-
view
81 -
download
2
Transcript of ICMMES-2004-68
![Page 1: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/1.jpg)
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Dr.-Ing. Norbert Grün Aerodynamics Simulation International Conference for Mesoscopic Methods in Engineering and Science Braunschweig, Germany July 26-29, 2004
![Page 2: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/2.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 2
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Outline
– PowerFLOW key features
– CFD simulation process
– Validation examples
– Various applications
– Conclusion
![Page 3: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/3.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 3
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
PowerFLOW Key Features
– Lattice-Boltzmann Method.
– Transient simulation.
– Low Re-#: Direct simulation without model assumptions.
– High Re-#: VLES (Very Large Eddy Simulation) in the fluid. Boundary Layer modeled by an extended log-law (accounting for longitudinal and crossflow pressure gradients).
– No manual meshing required: Automatic volume discretization using cubic cells (lattice) of different size (variable resolution).
– Automatic decomposition for parallel processing.
– Stable solutions.
![Page 4: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/4.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 4
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
CFD Simulation Process
CAD/CAS Model CATIA/ALIAS
Clay Model POLYWORKS
Simulation Model (Surface Facetization)
ANSA, QUICKMESH, THINK3, ...
1-5 Days
Simulation PowerFLOW
1 Day
Postprocessing PowerVIZ
Result
Shape Modification
of CAD/CAS Data
Morphing of the
Surface Mesh (PowerCLAY)
Turnaround
2-6 Days
![Page 5: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/5.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 5
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
CFD Process: Geometry Input
The surface
facetization
represents the
geometry only.
It does not set
the resolution
for the simulation.
Depending on the
level of detail up to
2-3 million facets
are used.
![Page 6: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/6.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 6
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
CFD Process: Modular Assembly
The complete
configuration may
be composed of
any number of
components.
Components may
be arranged in an
arbitrary fashion
and also intersect
each other.
![Page 7: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/7.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 7
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
CFD Process: Automatic Discretization
Typical voxel counts
for external aerodynamic
cases range from 20-80
milion cells.
Geometry representation
embedded in a lattice of
cubic cells (with different
levels of resolution).
![Page 8: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/8.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 8
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
CFD Process: Transient Simulation
100,000 Timesteps
(1 Timestep = 4.7 10-6 sec.)
No explicit convergence criterion, user monitors key quantities to decide when to stop the simulation.
Averaging Window
![Page 9: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/9.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 9
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Validation Models (Scale 1:2.5).
5series touring
Open Convertible
5series Limousine with/without Mirror
![Page 10: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/10.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 10
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Validation: Aerodynamic Forces
CZ2
0.114 0.105
CZ1
0.067 0.070
PowerFLOW 3.4: 0.252
CX
BMW Windtunnel: 0.252
CZ1
CZ2
-0.038 0.009 -0.027 0.006
PowerFLOW 3.4: 0.276
CX
BMW Windtunnel: 0.292
![Page 11: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/11.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 11
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Validation: Surface Pressure Distribution
Top Centerline (Geometry not to scale)
PowerFLOW Experiment
Bottom Centerline (Geometry not to scale)
![Page 12: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/12.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 12
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Validation: Near Surface Flow Topology
![Page 13: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/13.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 13
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Validation: Wake Velocity Magnitude
Hot Wire Anemometry
PowerFLOW 3.4
![Page 14: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/14.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 14
0,300
0,320
0,340
0,360
0,380
0,400
0,420
0,440
Serie LT Sport
Cx *
A
Windkanal
(Aschheim)
PowerFLOW
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Validation: Motorcycles (Windshield Variations)
Hot Wire Measurement PowerFLOW
Serie
LT
Sport
![Page 15: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/15.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 15
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Analysis of Drag Generation
-0,06
-0,04
-0,02
0,00
0,02
0,04
0,06
0,08
0,10
0,0 0,1 0,3 0,4 0,5 0,6 0,7 0,9 1,0
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,400,0
Cx(x) Verteilung
Cx(x) Integral
PowerFLOW 3.4: 0.371
CX
BMW Windtunnel: 0.382
![Page 16: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/16.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 16
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Analysis of Lift Generation
-0,03
-0,02
-0,01
0,00
0,01
0,02
0,03
0,0 0,1 0,3 0,4 0,5 0,6 0,7 0,9 1,0
-0,40
-0,30
-0,20
-0,10
0,00
0,10
0,200,0
Cz(x) Verteilung
Cz(x) Integral
CZ1 CZ2
0.011 0.013 0.143 0.123
PowerFLOW 3.4
BMW Windtunnel
![Page 17: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/17.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 17
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Visualization: Transient Surface Pressure
![Page 18: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/18.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 18
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Visualization: Near Wall Streamlines
![Page 19: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/19.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 19
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Visualization: 3D Streamlines
Colors represent Near Surface Velocity Distribution
![Page 20: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/20.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 20
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Visualization: Transient Flow Field Slices
![Page 21: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/21.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 21
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Visualization: Time Averaged Flow Field Slices
![Page 22: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/22.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 22
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Visualization: Transient Isosurface Cpt=0
For Cpt=0 the total pressure loss is equivalent to the dynamic free stream pressure
![Page 23: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/23.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 23
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Visualization: Time averaged Isosurface Cpt=0
Isosurface sweeping from high to low total pressure losses
![Page 24: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/24.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 24
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Visualization: Transient Isosurface VX=0
Reverse flow (Vx<0) inside the isosurface
![Page 25: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/25.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 25
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Applications: NASTRAN Interface (Structure)
Select parts per PID
Match NASTRAN parts
with the PowerFLOW model
PLOADs [N/mm2]
on the PowerFLOW model
Map area loads onto
the NASTRAN model
Forces on
individual parts
![Page 26: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/26.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 26
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Applications: ABAQUS Interface (Heat Transfer)
Mapping heat transfer coefficients
from a PowerFLOW simulation
onto an ABAQUS structure model
![Page 27: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/27.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 27
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Applications: Motorsports Aerodynamics
Total
Aerodynamic
Force
Velocity Magnitude
Static Pressure Total Pressure Streamlines
Static Pressure
![Page 28: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/28.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 28
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Applications: Motorsports Aerodynamics
Total
Aerodynamic
Force
Velocity Magnitude
![Page 29: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/29.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 29
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Applications: Underhood Flow
![Page 30: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/30.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 30
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Applications: Motorcycles - Transient Flow Field
![Page 31: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/31.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 31
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Applications: Electronics Cooling
Goals: qualitatively – Heat Transfer Distribution
quantitatively – Surface Temperatures
Heat Transfer Coefficient
Velocity Magnitude
![Page 32: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/32.jpg)
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004
Page 32
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
Conclusions
Short preprocessing phase due to automatic meshing. Capability to handle complex geometries. Steep learning curve due to ease-of-use. Does not require a numerics expert. Optimization loops still slower than the wind tunnel. Hardware requirements high for rapid turnaround.
![Page 33: ICMMES-2004-68](https://reader030.fdocuments.net/reader030/viewer/2022032506/55caedf7bb61eb8a4f8b4635/html5/thumbnails/33.jpg)
Thank you for your attention.
Industrial Applications of a Lattice-Boltzmann Code in Vehicle Aerodynamics.
BMW Group Dr. Norbert Grün International Conference for Mesoscopic Methods in Engineering and Science,
July 26-29, 2004