Vortex Induced Aerodynamic Forces on a Flat Plate in Ground Proximity

Abstract

Resumen en Ingles: A computational analysis of large-scale vortex generators in ground proximity was performed in order to predict the forces and flow structures induced underneath a flat plate model for a range of ride-heights. The investigation focused in two different set of experiments: assessment of the aerodynamic characteristics of different vortex generators shapes and the effect of the addition of side endplates. To effectively resolve the numerical turbulent flow RANS method with K- SST turbulence model was used. Amongst all the shapes of the simulated vortex generators, it was observed that the rectangular VG was the most efficient design, being able to generate the highest aerodynamic loads and suction peaks. In turn, it was found the triangular VG produced the highest vorticity peak values in the early stages of vortex shedding. The configuration of the endplates on the flat plate induced an additional dominant lower edge vortex that strongly contributed to the rate of change of the negative lift and drag gradients. It was observed that the downforce enhancement was directly related to the strengthening of the vortex and the change in the pressure distribution. From computational vorticity flow patterns was shown that the increase of vane spacing reduces the interaction of the vortices. Likewise, the increase of vane incidence angle from β=10o to β=20o indicated the appearance of the vortex burst as the ride-height of the model was reduced. A comparison of this model with the one without endplates showed the beneficial effects of using side plates. At the maximum downforce location (h/c=0.02) for β=20o, a favourable difference of 48.5% can be obtained, generally improving the downforce coefficient from CL=0.35 to CL=0.52.