Vortex breakdown as an aerodynamic control

The economic and environmental issues related on fuel consumption become gradually a major key point when car manufacturers are designing new vehicles.

Aerodynamic performance is one of the main levers (among other: mass diminution and engine optimization) to improve energetic efficiency of vehicles, since the drag force contributes for a major part of the power consumption for high speed (over 70 km/h). Depending on the exact shape of the vehicle, low-pressure structures can appear at the rear end of the car when the incoming air flow encounters geometric singularities (abrupt change of angle, deflectors, etc.). All these low-pressure structures form a drag force and are responsible of an increase of power consumption.

The collaboration between Groupe PSA and the LFMI laboratory (Pr. François Gallaire) aims at working to a vortex breakdown aerodynamic control: the idea consists in suppressing the low-pressure zone due to highly energetic streamwise vortices that can be found on vehicle with a particular angle of rear-end window.

This collaborative research project takes part in the framework of a PhD thesis between Groupe PSA and the M2P2 laboratory at Marseille and has already led to capture the 3D time-averaged behavior of streamwise vortices on a simplified car. The objective of this research is now to perform a linear stability analysis to obtain suggestions on where and how aerodynamic control should be applied to promote the bursting of such vortices.

Principal investigator Prof. François Gallaire
Sponsor Groupe PSA
Period 2014
Laboratory LFMI
Partner Université de Marseille
Collaboration TRACE