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The Aerodynamic Development of the New Jaguar XFDevelopment Of The New Jaguar Xf

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Why is the Jaguar XF a lower-drag vehicle than the S-Type it replaced? What was the aerodynamics development process followed?

Published as:
Gaylard AP (2008) The Aerodynamic Development of the New Jaguar XF. In, 7th MIRA International Conference On Vehicle Aerodynamics. 22nd -23rd October 2008, Coventry, UK. ISBN 978 1 906400 05 7

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The Aerodynamic Development of the New Jaguar XFDevelopment Of The New Jaguar Xf

  1. 1. The Aerodynamic Development of the New Jaguar XF Adrian Gaylard Technical Specialist – Aerodynamics & CFD
  2. 2. Overview <ul><li>The Task </li></ul><ul><li>The Process </li></ul><ul><li>The Achievement </li></ul><ul><li>Conclusions </li></ul>
  3. 3. The Task - The Jaguar S-Type <ul><li>Drag coefficient (C D ) of 0.31, (2.7L diesel variant) </li></ul><ul><li>Lift coefficients of 0.040 (C Lf ) at the front axle and 0.160 (C Lr ) at the rear. </li></ul><ul><li>(Based on a 2.27 m 2 frontal area) </li></ul>
  4. 4. The Task <ul><li>The first production Jaguar saloon with a C D below 0.3 </li></ul><ul><li>Improved lift distribution between front and rear axles </li></ul><ul><li>Coping with enhanced cooling flows (larger cooling apertures) </li></ul><ul><li>Working with a new style language and other changes </li></ul><ul><ul><li>large haunches </li></ul></ul><ul><ul><li>increased track and overhangs </li></ul></ul><ul><ul><li>bigger wheels </li></ul></ul><ul><ul><li>lower sump and re-designed exhausts. </li></ul></ul><ul><li>An S-Type with these features would have a C D of 0.34. </li></ul><ul><li>0.05 drag task (  C D ) </li></ul>
  5. 5. The Task - S-Type Aerodynamics
  6. 6. The Process – Product Development
  7. 7. The Process – Starting Point
  8. 8. The Process – Geometry Changes
  9. 9. The Process – Geometry Changes Before After
  10. 10. Process – CFD and Correlation
  11. 11. MIRA Full Scale Wind Tunnel 35 m 2 Closed Jet Process – Full-Scale Wind Tunnels
  12. 12. Volvo WT 27 m 2 Slotted Wall 200km/h + Moving Belt Rotating Wheels Process – Full-Scale Wind Tunnels
  13. 13. The Process – Full Scale Testing
  14. 14. The Process – Full Scale Testing
  15. 15. The Process – Related Attributes <ul><li>Soiling & Water management </li></ul>Competitor Jaguar XF
  16. 16. The Achievement – The Jaguar XF
  17. 17. The Achievement - Drag Relative to S-Type S-Type XF
  18. 18. The Achievement - Drag Relative to S-Type S-Type XF
  19. 19. The Achievement - Drag Relative to S-Type S-Type XF
  20. 20. The Achievement - Underbody
  21. 21. Conclusions <ul><li>The lowest Jaguar C D so far was delivered with </li></ul><ul><ul><li>About 250 CFD simulations </li></ul></ul><ul><ul><li>Around 600 hours of aerodynamics wind-tunnel testing </li></ul></ul><ul><ul><ul><li>120 hours of moving ground testing. </li></ul></ul></ul><ul><li>No impediment from removing model-scale testing from the process </li></ul><ul><li>CFD in combination with an economical wind-tunnel was effective </li></ul><ul><li>Full Scale Wind-Tunnel testing is essential </li></ul><ul><ul><li>Confirmation of CFD direction </li></ul></ul><ul><ul><li>Better evaluation of aerodynamic lift </li></ul></ul><ul><ul><li>Evaluation of yawed onset flows </li></ul></ul><ul><ul><li>Support for related attributes </li></ul></ul>

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