DOI: 10.1615/TSFP4
A DNS STUDY OF REYNOLDS-NUMBER DEPENDENCE ON PRESSURE FLUCTUATIONS IN A TURBULENT CHANNEL FLOW
SINOPSIS
DNS of a turbulent channel flow has been carried out at four Reynolds numbers, 180, 395, 640 and 1020, based on the friction velocity and the channel half width in order to investigate the Reynolds-number dependence on the pressure fluctuations. It is shown that large peaks appear in the streamwise spectra of the wall pressure fluctuations at low wavenumbers for the Reynolds numbers investigated. The origin of the peaks is examined using the pressure splitting method such as the rapid and slow parts. At higher Reynolds number, a closer examination reveals that large-scale patterns of the instantaneous wall pressure fluctuations are essentially associated with large-scale structures of the instantaneous rapid pressure in the outer layer, which causes the noticeable peaks in the wall pressure spectra at low wavenumbers.