THE UNSTEADY PRESSURE SIGNATURE OF TRANSONIC SHOCK WAVE/BOUNDARY LAYER INTERACTION

摘要

The statistics of wall pressure fluctuations beneathrna turbulent boundary layer interacting withrna normal shock wave are investigated exploitingrna direct numerical simulation (DNS) database. Inrnthe zero-pressure-gradient region upstream of therninteraction pressure statistics well compare withrncanonical boundary layers in terms of fluctuationrnintensities and frequency spectra. Pressure fluctuationsrnattain large values across the interactionrnzone, with an increase of about 7 dB from thernupstream level. The main effect of the interactionrnon the frequency spectra is to promote thernlow-frequency Fourier modes, and to inhibit thernhigh-frequency ones. Excellent collapse of frequencyrnspectra is observed past the interactionrnzone when data are scaled with the local boundaryrnlayer units. In this region an extended w?7/3rnpower-law behavior is observed, associated withrnthe suppression of mean shear caused by the imposedrnadverse pressure gradient.