Oscillatory behaviors of multiple shock waves to upstream disturbances

The oscillatory response of multiple shock waves to upstream disturbances in a supersonic flow is studied numerically constant area rectangular duct. accelerated through nozzle with an exit Mach number 1.75 and continues the duct, where are formed. To investigate effect disturbance on oscillations, three parameters varied systematically: turbulent intensity, frequency pressure fluctuation, amplitude fluctuation. wall shear stress variation along duct length provides location separation reattachment points field. spectra were used low-frequency unsteadiness oscillations. power spectral density static probability function (PDF) analyzed, results suggest that as intensity increased, dominant oscillation increased oscillations become more symmetrical. As symmetrical follow Gaussian curve closely. wave oscillates same excitation when increased. At large values amplitude, PDF shows deviation from Gaussian, rms increases monotonously. higher amplitudes excitation, traces train leading-edge display path-dependence characteristics.