Active vortex flow control on a generic delta wing

The flow around delta wings is dominated by a leading-edge vortex system, which induces increased velocities above the wing hence producing high suction peaks. These are responsible for the lift needed at high angle of attack aircraft maneuvering. In the flight regime beyond stall the flow separating from the leading-edge encounters a very steep adverse pressure gradient and consequently doesn't roll up into a vortex-like structure. Rather, encloses a massive dead-water region over the entire wing. With unsteady jet blowing at the leading edge additional momentum is created that reattaches the flow at the wing surface thus increasing the lift significantly. The investigated flow control method can be applied for extending the flight envelope, increasing maneuvering capability and flight stability. This flow manipulation technique is investigated on a generic half wing model at a very high angle of attack (α = 45°) in a low speed wind tunnel using force measurements and stereoscopic particle image velocimetry. Assessment of different actuation strategies is comprised in this study, in which blowing frequency and relative phase shift of the blowing momentum are kept constant and also modulated along the leading-edge.