Time-series analyses of wall pressure fluctuations in plume-induced separated flowfields

The separation shock wave motion in a plume-induced, boundary-layer separated flowfield was studied experimentally. The statistical properties of the shock wave motion were determined over the intermittent region using time-series analyses of wall static pressure fluctuation measurements. The standard deviation of the pressure fluctuations, nondimensionalized by the local mean pressure, reached a maximum of 0.22 near the middle of the intermittent region. The ratio of the maximum standard deviation of the pressure fluctuations over the intermittent region to the mean pressure difference across the intermittent region was calculated to be 0.43 for this flowfield. Both of these quantities demonstrate that the unsteady pressure loading caused by the shock wave motion has essentially the same magnitude in plume-induced separated flowfields as in flowfields produced by solid boundary protuberances.