Experimental investigation of hypersonic flow induced separation over double wedges

Flow separation occurs over the compression comers generated by deflected control surfaces on hypersonicre-entry vehicles and in the inlet of scram jet engines. Configurations like a double wedge and double cone modelare useful for studying the separated flow features. Flow fields around concave corners are relatively complicatedand produce several classical viscous flow features depending on the combination of the first and second wedgeor cone half apex angles. Particularly characteristic phenomena are mainly shock/ boundary layer, shock/shockinteraction, unsteady shear layers and non-linear shock oscillations. Although most of these basic gas dynamicscharacteristics are well known, it is not clear what happens at high enthalpy conditions. This paper reports a resultof flow fields over a double wedge at a stagnation enthalpy of 4.8 MJ/kg. The experiment was carried out in a freepiston shock tunnel at a nominal Mach number of 6.99. Schlieren and double exposure holographic interferometrywere applied to visualize the flow field over the double wedge.