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


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.


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


Length of the Ahmed body


Rear window length


Width of the Ahmed body


Total height of the Ahmed body


Height of the geometry front part


Width of the geometry front part


Reynolds number based on the geometry length

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

Viscous shear stress tensor

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

Turbulent shear stress tensor


Farfield total pressure


Static pressure


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


Transversal section immediately downstream of the bluff body


Static pressure coefficient




Angle between the rear window and the upstream flow direction


Skew angle


Orientation angle of the splitter plate related to the body


Angle between the splitter plate and the velocity V o


Aerodynamic drag coefficient


Reference aerodynamic drag coefficient


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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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