The structure of wall pressure fluctuations beneath a turbulent boundary layer interacting with a normal shock wave is investigated through direct numerical simulation (DNS). In the zero-pressure-gradient (ZPG) region upstream of the interaction pressure statistics well compare with canonical boundary layers in terms of fluctuation intensities and frequency spectra. Across the interaction zone, the r.m.s. wall pressure fluctuations attain large values (in excess of approximate to 162 dB), with an increase of about 7 dB from the upstream level. The main effect of the interaction on the frequency spectra is to enhance of the low-frequency Fourier modes, while inhibiting the high-frequency ones. Excellent collapse of frequency spectra is observed past the interaction zone when data are scaled with the local boundary layer units. In this region an extended omega(-7/3) power-law behavior is observed, which is associated with the suppression of mean shear caused by the imposed adverse pressure gradient.
Wall pressure fluctuations in transonic shock/boundary layer interaction / Pirozzoli, Sergio; Bernardini, Matteo. - 6:(2010), pp. 303-311. (Intervento presentato al convegno Proceedings of the IUTAM Symposium on Computational Aero-Acoustics for Aircraft Noise Prediction tenutosi a Southampton; England) [10.1016/j.proeng.2010.09.032].
Wall pressure fluctuations in transonic shock/boundary layer interaction
PIROZZOLI, Sergio;BERNARDINI, MATTEO
2010
Abstract
The structure of wall pressure fluctuations beneath a turbulent boundary layer interacting with a normal shock wave is investigated through direct numerical simulation (DNS). In the zero-pressure-gradient (ZPG) region upstream of the interaction pressure statistics well compare with canonical boundary layers in terms of fluctuation intensities and frequency spectra. Across the interaction zone, the r.m.s. wall pressure fluctuations attain large values (in excess of approximate to 162 dB), with an increase of about 7 dB from the upstream level. The main effect of the interaction on the frequency spectra is to enhance of the low-frequency Fourier modes, while inhibiting the high-frequency ones. Excellent collapse of frequency spectra is observed past the interaction zone when data are scaled with the local boundary layer units. In this region an extended omega(-7/3) power-law behavior is observed, which is associated with the suppression of mean shear caused by the imposed adverse pressure gradient.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
