Estimation of Spanwise Pressure Coherence Under a Turbulent Boundary Layer

The prediction of the streamwise and spanwise coherence length of the pressure field below a turbulent boundary layer at low Reynolds number generated using a recycling inflow method is estimated using different numerical large-eddy simulation models in an open-source finite-volume based computational fluid dynamics (CFD) package. Results for outer scaling mean and fluctuating velocity data are in good agreement with the PIV data, whereas the comparison with the DNSresults shows discrepancies in the viscous sublayer. The trend of the pressure spectrum is confirmed by the empirical model of Goody with a slightly faster decay at the higher frequencies. Regarding the streamwise and spanwise pressure coherence, the spanwise coherence length is significantly smaller than the streamwise coherence length, indicating low-amplitude structures. A mismatch in the low-frequency regime of the coherence length estimation is found between Corcos model and the numerical and experimental results, which likely will be solved when considering a higher-fidelity reference model.