Effects of unsteady trailing-edge blowing on delta wing aerodynamics

The effects of unsteady trailing-edge blowing on delta wing aerodynamics were investigated experimentally to understand the aerodynamics-propulsion interaction for dynamic thrust vectoring. Two models with sweep angles of A = 50 and 65 deg, representing nonslender and slender delta wings, respectively, were tested in a water tunnel. Flow visualization and velocity and force measurements were conducted at stall and poststall incidences. For the periodic blowing, it was found that the dynamic response of leading-edge vortex breakdown and wing normal force coefficient exhibit phase lags for both nonslender and slender delta wings. The estimated time constants are larger than those reported in the literature for unsteady wings undergoing pitching or plunging. In the case of transient blowing, the time delay for the decelerating jet is significantly larger than that for the accelerating jet. The variation of the circulation and the reattachment process near the wing surface were studied by means of velocity measurements. The range of the estimated time constants is similar at the stall and poststall incidences for both the slender and nonslender wings.