A detailed experimental study was performed in a supersonic isolator with incoming Mach numbers of 1.85 and 2.70 to investigate the potential of a micro-ramp as a form of shock train control. Two types of upstream wedges were arranged to produce flow fields with and without background waves (BWs). Wall pressure measurements of the primary and corner regions and schlieren visualization with multiple knife edges were performed to investigate the shock train flow field. The micro-ramp controlled flow fields of the shock train at the two incoming Mach numbers are found to show common characteristics. The micro-ramp suppresses the upstream propagation of the shock train and improves the ability of its downstream flow field to resist adverse pressure gradients. The control effect of the micro-ramp is enhanced in the shock train flow field with BWs. An incoming Mach number of 1.85 leads to shortening or even elimination of the Mach stem in the shock train leading edge under micro-ramp control, weakening the intensity of the shock, inhibiting the thickening of the boundary layer caused by the impingement of the shock, and slowing down the contraction of the supersonic core flow. The micro-ramp has little influence on the morphological structure of the shock train under an incoming Mach number of 2.70. The main control effect of the micro-ramp is to suppress the sudden jump of the shock train and prevent the large upstream movement of the shock train and large-area boundary layer separation that result from the sudden movement of the shock train under an incoming Mach number of 2.70.

• Received 3 May 2022
• Accepted 23 September 2022

DOI:https://doi.org/10.1103/PhysRevFluids.7.103401