Experimental investigation of flow separation over a step

Because of the growing importance of the base pressure phenomena at supersonic speeds, much attention has been drawn to the mechanism of flow separation behind a blunt base. In particular, Crocco and Lees [1] applied to the base pressure problem their general theory based on a flow model exhibiting interaction between the dissipative flow region and the nearly isentropic main flow. Their results could give the qualitative explanation for the observed phenomena. More recently, Korst [2] and Chapman, Kuehn and Larson [3] independently put forward a simple method of predicting the base pressure by dividing the flow into the dissipative “cavity” flow region wherein the pressure is assumed to be constant and a reattachment zone wherein the compression is assumed to be such that not much total pressure is lost along the dividing streamline.