Wing Rock Suppression Using Recessed Angle Spanwise Blowing

Abstract

Introduction O NE of the limitationsto combat effectivenessof Ž ghter aircraft is wing rock—a high angle-of-attack dynamic motion manifested primarily in a limit-cycle roll oscillationsphenomenon. It is an aerodynamicphenomenonthat causeslossof stabilityand control in the lateral/directional mode. The leading-edge vortices emanating from the high-performance Ž ghter aircraft are one of the main causes of wing rock at high angles of attack. An effective means of suppressing wing rock is through the direct control and manipulation of leading-edge vortices at these  ight regimes. The technique of “blowing”2i4 has been of greatest interest because it is found to be highly effective in controlling the vortex orientation. This Note involves the experimental implementation of one such blowing technique—recessed angle spanwise blowing (RASB), using a simple rule base controller to a slender delta wing model in a lowturbulence wind tunnel. Through interpretation of the observations and results obtained from the experiments,an analysis is conducted to assess the effectiveness of RASB in suppressing wing rock. The results are substantiated by the  ow visualization experiments and force balance experiments. The excellent correlationsof the results and observations demonstrate the effectiveness of the RASB technique in its stipulated role of wing rock suppression.