On the space-time characteristics of wall-pressure fluctuations

A database obtained by direct numerical simulation of turbulent channel flow was used to compute the three-dimensional frequency/wave-number spectrum of wall-pressure fluctuations. The spectrum was used to deduce scaling laws for pressure fluctuations and to evaluate the similarity form for the power spectrum. The convection velocity as a function of frequency, wave number, and spatial and temporal separations was calculated and compared with the experimental data. The problem of artificial 'acoustics' in numerical simulation of incompressible flows is discussed.