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