Numerical drag reduction studies of generic truck models in ground effect using active flow control

In a previous paper AIAA 2009-4013, the effect of active flow control (AFC), using oscillatory blowing (synthetic jets) on drag reduction of trucks in ground effect was numerically studied using the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations. Two generic models of trucks for which the experimental data are available were considered in the simulations. CFD simulations were in good agreement with the data. Both the experiments and simulations showed that 10 to 15% reduction in drag can be achieved by active flow control using oscillatory blowing. It was shown that a combination of oscillatory blowing and steady blowing or suction at appropriate locations on the rear face of the truck can further reduce the drag. In this paper, we study the effect of ground on the truck drag reduction using AFC. These studies indicate that the AFC techniques can be intelligently employed to achieve significant reduction in aerodynamic drag of the vehicle.