Control of leading-edge vortices on non-slender delta wings

Abstract

Wind tunnel experiments were conducted in order to investigate the effectiveness of flow control devices on a non-slender delta wing. Main objective of testing was to determine the effect on the rolling moment of different modifications of the left leading edge. As a clean configuration a flat delta wing model with round leading edges and a sweep angle of L = 53° was used. Tests were conducted in the open test section of a low-speed atmospheric wind tunnel at Reynolds numbers Re = 0.3M - 1.2M. The angle of attack was varied from a = 0° to 34°. Various modifications and actuators were tested. These include a flat bar projecting out of the round leading edge (static and oscillating) and a rotatable cylinder having a straight edge milled into its surface (replacing the round leading edge). Forces and moments were obtained by a 6-component strain gauge and surface flow topologies by oil flow visualization. In certain cases also the vortical flow field above the surface was visualized by smoke. Results obtained with the various flow control configurations will be presented and discussed.