An experimental study on the compressible ramp was conducted. The mean surface pressure distributions indicate the upstream movement of the
detached shock with increasing ramp angle at Mach 1.28. The subsonic
ramp flows at Mach 0.64 and 0.83 show the strong inviscid-viscous
interactions. The upstream compression can be scaled with the similarity
parameter Mα, and the upstream and downstream pressure gradients are
associated with the ramp angle and quadratic function of the freestream
Mach number. The analysis of surface pressure fluctuations for all the test cases indicates that the presence of a ramp has a minor effect on the
unsteadiness of the flows.