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Experiments in Fluids

, Volume 48, Issue 1, pp 1–16 | Cite as

Aerodynamic drag reduction by vertical splitter plates

  • Patrick Gilliéron
  • Azeddine Kourta
Research Article

Abstract

The capacity of vertical splitter plates placed at the front or the rear of a simplified car geometry to reduce drag, with and without skew angle, is investigated for Reynolds numbers between 1.0 × 106 and 1.6 × 106. The geometry used is a simplified geometry to represent estate-type vehicles, for the rear section, and MPV-type vehicle. Drag reductions of nearly 28% were obtained for a zero skew angle with splitter plates placed at the front of models of MPV or utility vehicles. The results demonstrate the advantage of adapting the position and orientation of the splitter plates in the presence of a lateral wind. All these results confirm the advantage of this type of solution, and suggest that this expertise should be used in the automotive field to reduce consumption and improve dynamic stability of road vehicles.

Keywords

Wind Tunnel Orientation Angle Drag Reduction Aerodynamic Drag Total Pressure Loss 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

List of symbols

LA

Length of the Ahmed body

lA

Rear window length

wA

Width of the Ahmed body

HA

Total height of the Ahmed body

h

Height of the geometry front part

w

Width of the geometry front part

Re

Reynolds number based on the geometry length

\( \overline{\overline{{\tau_{\mu } }}} \)

Viscous shear stress tensor

\( \overline{\overline{{\tau_{t} }}} \)

Turbulent shear stress tensor

Pio

Farfield total pressure

P

Static pressure

dσ

Surface element

\( \vec{n} \)

Normal vector unit

\( \vec{x} \)

Vector unit in the longitudinal plane

\( \Upsigma \)

Surface of the outlet boundaries around Ahmed body (\( \Upsigma = \Upsigma_{\text{L}} + S_{\text{e}} + S_{\text{s}} + S_{\text{c}} \))

\( \Upsigma_{\text{L}} \)

Lateral surface

\( S_{\text{e}} \)

Inlet section (engine compartment)

\( S_{\text{s}} \)

Outlet section (engine compartment)

\( S_{\text{c}} \)

Body surface

\( \vec{V}_{0} \)

Upstream velocity vector

\( \vec{V} \)

Local velocity vector

Vx, Vy, Vz

Velocity components

\( (\vec{x},\,\vec{y},\,\vec{z}) \)

Vector unit system related to the model

S

Transversal section immediately downstream of the bluff body

Cp

Static pressure coefficient

ρ

Density

α

Angle between the rear window and the upstream flow direction

β

Skew angle

λ

Orientation angle of the splitter plate related to the body

θ

Angle between the splitter plate and the velocity V o

Cd

Aerodynamic drag coefficient

Cdref

Reference aerodynamic drag coefficient

References

  1. Ahmed SR, Ramm R, Faltin G (1984) Some salient features of the time averaged ground vehicle wake. SAE technical Paper Series 840300Google Scholar
  2. Ardonceau P, Amani G (1992) Remarks on the relation between lift induced drag and vortex drag. Eur J Mech B 11(4):455–460Google Scholar
  3. Arnald D, Cousteix J, Michel R (1976) Couche limite se développant avec gradient de pression positif dans un écoulement extérieur turbulent, La Recherche Aérospatiale, n°1976-1Google Scholar
  4. Baudoin JF, Aider JL (2008) Drag and lift reduction of a 3D bluff body using flaps. Exp Fluids 44:491–501. doi: 10.1007/s00348-007-0392-1 CrossRefGoogle Scholar
  5. Cousteix J (1989) Aérodynamique, Turbulence et Couche Limite. Cepadues-Editions, Toulouse, pp 11–14Google Scholar
  6. Gad-el-Hak M (1996) Compliant coatings: a decade of progress. In: Workshop on flow control—fundamentals and practices, Cargèse, Corse, 1996Google Scholar
  7. Gilliéron P, Chometon F (1999) Modelling of stationary three dimensional detached airflows around an Ahmed reference body. In: Proceedings of the third international workshop on vortex, ESAIM, vol 7, pp 173–182Google Scholar
  8. Granville PS (1985) Mixing length formulation for turbulent boundary layers over arbitrarily rough surfaces. J Ship Res 29(4):223–233Google Scholar
  9. International Energy Agency (IEA) (2007) World energy outlook 2007—China and India insights (executive summary). International Energy Agency, ISBN: 978-92-64-02730-5Google Scholar
  10. Kourta A, Vitale E (2008) Analysis and control of cavity flow. Phys Fluids 20:0771041 (10 pp)Google Scholar
  11. Levallois E, Gilliéron P (2005) Contrôle des écoulements en aérodynamique automobile & réduction de traînée par éléments séparateurs - Analyse par PIV, Colloque National de Visualisation et de Traitement d’Images en Mécanique des Fluides, Fluvisu11, Lyon, 6–9 juinGoogle Scholar
  12. Mair WA (1965) The effect of a rear mounted disc on the drag of a blunt based body of revolution. Aeronaut Q 16:350–360Google Scholar
  13. Onorato M, Costelli A, Garonne A (1984) Drag measurement through wake analysis, SAE, SP-569. In: International congress & exposition, Detroit, MI, 27 February–2 March 1984, pp 85–93Google Scholar
  14. Passenger Cars, University of Sheffield and University of Michigan, Produced by SASI Group (Sheffield) and Mark Newmann (Michigan), Map031, 2006Google Scholar
  15. Roshko A, Koenig K (1978) Interaction effects on the drag of bluff bodies in tandem. In: Sovran G, Morel T, Mason WT (eds) Aerodynamic drag mechanisms of bluff bodies and road vehicles. Plenum, New York, pp 253–286Google Scholar
  16. Rossiter JE (1964) Wind tunnel experiments on the flow over rectangular cavities at subsonic and transonic speeds. Aeronautical Research Council Reports and Memo n° 3438Google Scholar
  17. Spohn A, Gilliéron P (2002) Flow separations generated by a simplified geometry of an automotive vehicle. In: IUTAM symposium on unsteady separated flows, Toulouse, France, 8–12 April 2002Google Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Research Division, Fluid Mechanics & AerodynamicsRenault GroupGuyancourtFrance
  2. 2.Institut PRISME, ESAPolytech’OrléansOrleans Cedex 2France

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