Experimental evidence is presented in support of a model of separation shock unsteadiness developed by Plotkin [AIAA J. 13, 1036 (1975)]. Under this model, the position of the separation shock follows linearly damped Brownian motion. The model describes the manner in which relatively broad-band perturbations in the incoming flow lead to relatively low-frequency motion of the separation shock. Close agreement was found between the predictions of the model and the autospectra and autocorrelations of wall pressure fluctuations and shock position fluctuations for several blunt fin flows at Mach 3 and Mach 5. Given the similarity of the power spectra of wall-pressure fluctuations for a variety of separated, supersonic flows, this description may have broad applicability.
All Science Journal Classification (ASJC) codes
- Computational Mechanics
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Fluid Flow and Transfer Processes