LCVTP Dissemination Event
Workstream 12
Aerodynamic Efficiency
Coventry University Programme Manager and WS12 Leader:
Mike Dickison
WS12 Technical Leader:
Trevor Haynes
18th May 2011
Workstream 12 Aerodynamic Efficiency
Collaborators:
• Coventry University (Lead)
• MIRA
• Ricardo
• JLR
• TMETC
Workstream 12 Aerodynamic Efficiency
High Level Workstream Tasks
• Task 12.1 technology benchmark study and concept selection
• Task 12.2 concept evaluation study
• Task 12.3 conceptual packaging study
• Task 12.4 conceptual vehicle styling/ aerodynamic performance integration
• Task 12.5 aerodynamic simulation and testing
• Task 12.6 implementation and evaluation
Colour Code: Green = Completed, Amber = In Progress, Black = Not Yet Undertaken
LCVTP Dissemination Event
WS12 Aerodynamics
Trevor Haynes Coventry University 18th May 2011
Contents
> Aerodynamic research/investigation
• Drag reduction ( V2, depends on Cd.A)
• Base pressure recovery
• Wheels and wheel arches
> Wind tunnel techniques and processes (MIRA)
• Flow visualisation (helium bubble) (LVAV)
• Computational fluid dynamics (CFD) process with open source software
> Effect of aerodynamic improvements (Ricardo)
• Drive cycle definitions
• Vehicle use, type, and aerodynamic parameters
Aerodynamic Testing:
Areas for Research / Investigation
•Base pressure recovery (BPR)
•Rear end taper (active?) •Vortex generators
•Base cavities & bleed •Base plates
•Diffuser
•Wheels and wheel arches (WWA)
•Wheel covers (active?) •Ducted flows, air ‘curtain’ or jets
•Wheel arch blockage •Turning vanes
•Active fairings
Aerodynamic Testing:
CFD, Scale Models and Vehicles
Method Location Model Scale [%]
CFD Coventry Uni
Mair body -
MIRA Ref Car -
MIRA/JLR X351 -
Model WT
(External
Research)
Cranfield Uni Tata LCTVP 30
Rotating wheel rig 80
Durham Uni Bluff body (Ahmed) 25 Pressures, PIV
Loughborough Uni Windsor /Audi A2 25 PIV
CFD &
scale models
Full scale
models &
Vehicles
Method Location Model
FSWT MIRA
Audi A2
Freelander
MIRA Reference Car
X351 Aerobuck
MG FSWT? Fra , Ita,? Audi A2
X351 Aerobuck
Models for Base Pressure Recovery
(BPR) Investigation
MIRA Reference Models
Mair Body (1969)
Model Wheel Investigations
Rotating Wheel Rig
Cranfield Uni. 8x6ft wind tunnel
Full Scale Vehicles
MIRA Reference Car Jaguar XF (Aerobuck)
Audi A2 Land Rover Freelander
Aero Testing Support (CU)
• Manufacture
> LCVTP 30% model
> Parts for MIRA RM 30%
> Audi 25% mirrors & spoiler
> MIRA RM 100% rears & diffuser ‘filler’
• Scanning
> Training course
> A2 & MIRA models
• CAD
> LCVTP model
> MIRA model components
Techniques and Processes (CU)
• CFD – Star CCM+
> Training
> Investigate the Mair body - effects of changing base geometric
features associated with vehicle shapes
> Licences:120 at CU available for aerodynamics.
Techniques and Processes (MIRA)
• OpenFOAM process fully developed for external aero application.
• Correlated with wind tunnel data to examine complex scenarios
• He Bubble Development - Several wind tunnel tests used to show bubble
flow visualization (achieved at wind speed in excess of 20m/s)
Aerodynamic Testing
• FS Tests of X351, MIRA Reference Car, Freelander & Audi A2 (MIRA,
JLR, CU)
• Investigations into BPR and WWA
Aerodynamic Testing (continued)
Aerodynamic Testing
Initial results
Audi A2: Effect of modifications on Cd
Cd reduction ≈ 33%
Effect of Aerodynamic Drag on
performance
> CO2 production from aerodynamic effect can be 8x that from
NEDC (Islam, 2009)
Drive Cycle Analysis (Ricardo)
Method
• V-SIM tool
• Single drive cycle in EV mode
• 8 drive cycles
• Three vehicle classes: A,C,E
• Cd range 0.20-0.36
• A ranges A: 1.7-2.3, C: 1.8-2.5, E: 2.0-2.8m2
• Effect on electrical energy consumption regenerative braking
potential, and range with and w/o regenerative braking
Drive Cycle Analysis (Ricardo)
Result
Drive Cycle Analysis (Ricardo)
Results/Conclusions
• Illustrate improvements from reducing drag
• Effects of various cycles on improvements
• Greater gains in high speed cycles
> Consumption on low speed cycles “..largely unaffected..”
• Reduced drag increases energy recovered in braking
> Small in city cycles
• For A segment, larger proportional gains by improving drag
Next Steps…….
• Aerodynamic R&D
> Continued research into base pressure recovery and wheel and wheel
arches (14 out of 34 shifts used in 2011)
> Review finding from universities
> Realistic solutions
> Validation (further opportunities?)
• Moving ground wind tunnel test?
• Drive cycle analysis
• Techniques and processes R&D
> CFD Continued enhancement of process
> LVAV. Increased number of 10mm diameter bubbles
Next Steps …. (continued)
• Feasibility & design
• Dissemination
> LCVTP events
> SAE Congress, Detroit, Apr 2012
> MIRA Aerodynamics Conference, UK, Oct 2012
Summary
• Big (complex) aerodynamics programme
> 5 partners (5+ aerodynamicists)
• 3 sub-contracted Universities
> Models / test vehicles for preparation & test
• 3 CFD, 5 scale, 4 full scale
• Large support structure required
• Work started on BPR and WWA studies: CFD & W/T
• Initial results encouraging
• Investigation to continue based upon the results found
• Realistic proposal
Thanks & Acknowledgements
The WS12 team for their support