Abstract:
Low-speed wind tunnel tests have been made to investigate the flow around
a leading-edge vortex flap at the maximum L/D condition. Tests were also made to
measure the performance of the inverted vortex flap and the vortex plate. The force
measurements and flow visualization tests were conducted on a 60deg delta wing
model.
Results indicate that the lift to drag ratio is a maximum for any given flap
deflection angle when the flow comes smoothly onto the deflected vortex flap
without forming a large leading-edge separation vortex on the flap surface. The
benefit of the vortex plate is seen in the drag results which are smaller than those
for the datum wing. This benefit is due to some leading-edge suction acting on the
forward facing region between the delta wing and the vortex plate.
