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 layer interaction at Mach numbers of 1.3 and 1.5. The exper iment is one in which a naturally grown turbulent boundary layer on th e tunnel walls is disturbed by a normal shock wave spanning the test s ection of the tunnel. The shock wave is oscillated by a periodic press ure disturbance in the tunnel diffuser far downstream of the interacti on. Both instantaneous (spatially averaged) and time averaged results for the surface pressures are presented. These results are used to stu dy the flow development and phase changes through the interaction over a frequency range from 34 to 167 Hz. This frequency range was chosen to cover the range of parameters likely to occur in conditions corresp onding to stall flutter in the compressor fans of large bypass engines .