VISUALIZATION OF FLOW SEPARATION AND CONTROL BY VORTEX GENERATORS ON AN SINGLE FLAP IN LANDING CONFIGURATION

This paper focuses on a suppression of the flow separation, which occurs on a deflected flap, by means of vortex generators (VG's). An airfoil NA CA 63A421 with a simple flap and vane-type vortex generators were used. The investigation was carried out by using experimental and numerical methods. The data from the numerical simulation of the flapped airfoil without VG's control were used for the vortex generator design. Two sizes, two different shapes and various spacing of the vortex generators were tested. The flow past the airfoil was visualized through three methods, namely tuft filaments technique, oil and thermo camera visualization. The experiments were performed in closed circuit wind tunnels with closed and open test sections. The lift curves for both cases without and with vortex generators were acquired for a lift coefficient improvement determination. The improvement was achieved for several cases by means all of the applied methods.