Trailing-edge noise diagnostics with low-repetition-rate PIV

A novel approach for trailing-edge noise diagnostics with low-repetition rate Particle Image Velocimetry systems is presented. The approach is based on the application of diffraction theory and implements a recently developed single-snapshot pressure reconstruction in boundary layers using the Vortex-in-cell method in combination with a frozen turbulence assumption to estimate the relevant statistical descriptors of the surface pressure field. The present communication describes the required planar and tomographic Particle Image Velocimetry experiments with a high spatial-dynamic-range system and demonstrates the applicability of the approach by comparison of hydrodynamic and acoustic pressure statistics with available data. The frequency spectra of the hydrodynamic pressure near the surface are found to be sensitive to the model employed for the convective velocity in the application of the frozen turbulence assumption for reduced frequencies f δ*/u∞ > 0.5 (2.3kHz). For lower reduced frequencies, excellent agreement with the reference data is observed.