An Experimental Observation of 3-D Scramjet Inlet Flow in a Shock Tunnel

An experimental observation was carried out for three-dimensional scramjet inlet flow.Six 3-D inlet models with different swept and wedge angles were examined in a M4.5 straight shock tunnel to review the inner flow field of inlet model by means of high speed schlieren photography,oil dot visualization technology and surface tuft method,respectively.As a valuable supplement,2-D numerical simulation was also conducted.Schlieren photos clearly show the very complex flow structure in the inlet,which is mainly caused by the shock wave-boundary interaction.The shock wave interaction consists of shock waves and viscous separation regions.These phenomena are also confirmed by numerical simulation.Oil dot photos capture the flow patterns near the walls of the inlet.The fin shock,separation line and reattachment line can be identified.According to the experimental results,it is presumed that the interaction of shock wave caused by cowl with the boundary layer over the inlet top and the boundary layer over the sidewall are main flow structures,which deteriorate the flow field in the inlet.Pumping was used to control the separation,and presented some positive results.