Wall-pressure fluctuations in a turbulent boundary layer: a comparison of two LES models

The fluctuating wall-pressure on a zero-pressure-gradient flat-plate turbulent boundary layer (BL) was numerically investigated using a large eddy simulation (LES). The pressure fluctuations generate vibrations and noise, which are of interest in many applications involving fluid-structure interactions. In this work, the pressure frequency-wavenumber spectrum generated by two LES subgrid-scale (SGS) closures, namely: the constant-coefficient Smagorinsky-Lilly model and the stretched-vortex model, were compared to empirical, experimental, and simulated data.

The two LES closure models were first validated with results from literature. The stretched-vortex model showed good agreement in the first and second ordered statistics compared to existing data. The constant-coefficient Smagorinsky model followed the same trend when compared to data from literature. The wall-pressure fluctuations were assessed in terms of the frequency-wavenumber spectrum. Both models showed a clear convective region, which compared well with the empirical models. However, in the subconvective region, the constant-coefficient Smagorinsky model diverged from the empirical models, while the stretched-vortex model captured the low wavenumber region.