Aerodynamics of Large-Scale Vortex Generator in Ground Effect

The aerodynamic performance of several vortex generators (VGs) of the type used on the lower surface of race cars was tested in a low-speed wind tunnel. In this particular application, the vortices emanating from the VGs create a suction force between the vehicle and the ground, thereby improving tire adhesion and the vehicle’s cornering∕traction performance. Since the size of these devices is much larger than the local boundary layer thickness, they are termed “large scale” in this study. Results of the wind tunnel tests indicate that the aerodynamic adhesion forces increase with reduced ground clearance while the corresponding drag increase is much smaller. The parameters investigated in this study are the VG length, shape, and the effect of incidence angle. Amongst the various shapes tested, the traditional rectangular VG created the largest forces while the simple triangular design was the most efficient in terms of the incremental lift to drag ratio.