Spectral Characteristics of Separation Shock Unsteadiness

摘要

Spectra of wall pressure fluctuations caused by separation shock unsteadiness were compared for data obtained from wind tunnel experiments, the HIFiRE-1 flight test, and large-eddy simulations. The results were found to be in generally good agreement, despite varying Mach number and two orders of magnitude difference in Reynolds number. Relatively good agreement was also obtained between these spectra and the predictions of a theory developed by Plotkin, which depicts the separation shock unsteadiness as linearly damped Brownian motion. Further, the predictions of this theory are qualitatively consistent with the results of experiments in which the shock motion was synchronized to controlled perturbations. The results presented here support the idea that separation unsteadiness has common features across a broad range of compressible flows.