Behavior of wake vortices near ground

Direct numerical simulations of a vortex pair embedded in a stable atmospheric boundary layer are presented. The effects of various crosswind conditions are studied. These computations demonstrate the creation of secondary vortices for the range of Reynolds number (3.77 x 10(3) less than or equal to Re-Gamma less than or equal to 1.131 x 10(5)). The physics of wake vortex interactions with the ground for different values of crosswind are discussed, The redistribution of vorticity between the atmospheric boundary layer and the vorticity induced by the primary vortices may explain the vortex tilting phenomenon. A parameterization of the effect of crosswind on the minimum altitude reached by the two vortices is given.