DETECTION OF TURBULENT BOUNDARY-LAYER SEPARATION USING FLUCTUATING WALL PRESSURE SIGNALS

A technique for detecting intermittent, shock-induced, turbulent, boundary-layer separation has been developed and tested in a Mach 5 blowdown tunnel. The interactions were generated by “semi-infinite” circular cylinders. The method employs two miniature pressure transducers oriented streamwise and installed flush with the test surface. Through cross correlations of the conditionally sampled signals of the two transducers under the moving shock, it has been shown that the flow downstream of the instantaneous shock position is separated. The results indicate that in these flows, the separation location obtained from surface tracers, such as the kerosene lampblack method, is actually the downstream boundary of a region of intermittent separation. © 1990 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.