Identification of Sources of Wall Pressure Fluctuations Using Space–Time Pressure–Velocity Correlations

The origin and characteristics of large-scale pressure fluctuations have been attributed to the large-scale coherent motions in turbulent boundary layers, often termed “superstructures.” Existing studies lack a few key aspects, including limitations to lower Reynolds numbers, significant spatiotemporal aliasing, and limited measurement domains. This study uses synchronous wall-parallel stereoscopic particle image velocimetry (PIV) and wall-pressure measurements to quantify the characteristics of large-scale flow structures and their relationship with wall pressure fluctuations in a smooth-wall turbulent boundary-layer flow. These measurements are acquired at a friction Reynolds number [Formula: see text] in the upper part of the logarithmic layer ([Formula: see text]) under the influence of a small pressure gradient ([Formula: see text]). Space–time correlations reveal the presence of a correlation between wall pressure and velocity fluctuations. The wavenumber–frequency cross-spectra between wall pressure and velocity components are presented, showing the direct contribution of the streamwise and wall-normal velocity components in generating wall-pressure fluctuations, while the spanwise velocity component is considered insignificant.