Experimental Investigations on the Interaction of the Single/Co-Rotating Vortex with the Ground

Experiments on the interactions between a single vortex/co-rotating vortices and the ground were conducted in a water channel using particle image velocimetry (PIV) measurements. Both the single vortex (SNV) and co-rotating vortex pair (CVP) were generated by using NACA0012 vortex generators to simulate the main flow features behind one side of the wings at the farfield and near field. The ground effect was achieved by allocating a flat plate downstream of the vortex generators. It has been found that the lower initial vortex height led to greater vortex rebound and lateral drift in both the SNV and CVP cases, whereas the development of a secondary vortex was also promoted with lower initial vortex height. In the CVP cases, the mutual rotation of the primary vortices led to variation of the close-to-wall velocity distribution. This effect added the disturbances to the formation and evolution of the secondary vortical structure, which eventually affected the height of the secondary vorticity and the rebound of the primary vortices.