Prediction of Wall Pressure Spectrum using a RANS Calculation

Abstract

Steady turbulent flow fields obtained from solving the Reynolds Averaged Navier Stokes (RANS) equations with an isotropic model are used to predict the frequency spectrum of wall pressure fluctuations. The fluctuating turbulent velocity normal to the wall is represented by the turbulent kinetic energy contained in the local flow. An anisotropic distribution of the turbulent kinetic energy is implemented based on a turbulent boundary layer over a flat plate. The spectral correlation model for predicting the wall pressure fluctuations is obtained through a Green’s function formulation and modeling of the streamwise and spanwise wavenumber spectra. Predictions for a zero-pressure-gradient flow agree welll with measurements and reveal an overlap region of an inverse of the frequency, which has been proved as a resultant of the velocity profile in the logarithmic region. Spectrum predictions for flow over a backward facing step are used to demonstrate the robustness of the current approach for a non-zero-pressure-gradient flow with a flow recirculation and a reattachment region.