TIME-SERIES ANALYSES OF WALL-PRESSURE FLUCTUATIONS IN PLUME-INDUCED SEPARATED FLOWFIELDS

The separation shock wave motion in a plume-induced, boundary layer se parated flowfield was studied experimentally. The statistical properti es of the shock wave motion were determined over the intermittent regi on using time-series analyses of wall static pressure fluctuation meas urements. The standard deviation of the pressure fluctuations, nondime nsionalized by the focal mean pressure, reached a maximum of 0.22 near the middle of the intermittent region, The ratio of the maximum stand ard deviation of the pressure fluctuations over the intermittent regio n to the mean pressure difference across the intermittent region was c alculated to be 0.43 for this flowfield. Both of these quantities demo nstrate that the unsteady pressure loading caused by the shock wave mo tion has essentially the same magnitude in plume-induced separated flo wfields as in flowfields produced by solid boundary protuberances.