Numerical Investigation of Transonic Leading Edge Vortex Control By Steady Blowing

Abstract

Modern combat aircraft typically feature a delta wing design with highly swept leading edges. At low to moderate angles of attack, strong longitudinal vortices develop at these leading edges. However, at high angles of attack, vortex breakdown starts to occur, causing a change in lift distribution that might induce large aerodynamic loads. Commonly, mechanical control surfaces are used to influence the aerodynamic characteristics of these kinds of wings. An alternative is the use of active flow control, e.g. by using steady blowing. Within this study, the use of two different active flow control approaches, along-the-core blowing and spanwise blowing, to control the vortical flow above the DLR-F23 configuration is investigated numerically. For both approaches, the jet strength and orientation are systematically varied. Depending on the jet characteristics and free stream Mach number, both approaches achieve a moderate increase in lift of between 5% - 10%.