AN EXPERIMENTAL-STUDY OF THE INTERACTION OF AN UNSTEADY SHOCK WITH A TURBULENT BOUNDARY-LAYER AT MACH NUMBERS OF 1.3-AND-1.5

In this paper the results are given of an experimental investigation i nto the flow development and the surface pressures in an unsteady shoc k boundary interaction at Mach numbers of 1.3 and 1.5. The experimenta l is one in which a naturally grown turbulent boundary layer on the tu nnel is disturbed by a normal shock wave spanning the test section of the tunnel. The shock wave is oscillated by a periodic pressure distur bance in the tunnel diffuser far downstream of the interaction. Both i nstantaneous (spatially averaged) and time averaged results for the su rface pressures are presented. These results are used to study the flo w development and phase changes through the interaction over a frequen cy range from 34 to 167 Hz. This frequency range was chosen to cover t he range of parameters likely to occur in conditions corresponding to stall flutter in the compressor fans of large bypass engines.