Analysis of Shock and Vortex Breakdown Behavior in Unsteady Transonic Flow on A Slender Delta Wing

A transonic flow around delta wing with sharp leading edge is simulated by detached eddy simulation(DES)method. The behavior of the complex shock waves in unsteady flow on the top surface of delta wing is analyzed at moderate and high angles of incidence, as well as the movement of the location of vortex breakdown induced by the shock. Numerical results indicate that three normal shock waves exist on the top surface of delta wing at both incidence angles. At angle of incidence of alpha=18.5 degrees, the rear/terminating shock propagates upstream to the sting tip from trailing edge periodically, the strength of shock becomes weaker as it moves forward. Ultimately, the rear/terminating shock amalgamates with the normal shock wave at the sting tip. The location of vortex breakdown is close to the trailing edge. At angle of incidence of alpha=23 degrees, a second shock appears upstream of the sting tip, which moves analogically with the terminating shock for the case of alpha=18.5 degrees, it indicates that this shock is the rear/terminating shock having undergone an upstream shift with the increase of incidence. As while, the location of vortex breakdown induced by second shock moves periodically.