Data reduction from time-resolved tomographic PIV for unsteady pressure evaluation

With the development of high-speed PIV and tomographic PIV, a number of novel measurement approaches are emerging. One of those is “pressure-by-PIV” and enables the spatio-temporal pressure fluctuations generated by airflow to be measured in the fluid region as well over the surface of solid objects. This experimental method is based on the application of three-dimensional time-resolved velocity data and invokes the Navier-Stokes equations to evaluate the instantaneous pressure gradient field from the numerical evaluation of fluid acceleration, in the assumption of incompressible flow. A number of experiments conducted first by thin-volume tomographic PIV and later by fully volumetric tomographic PIV at measurement rates up to 10 kHz demonstrate the applicability of the PIV-based pressure evaluation to determine broadband pressure fluctuations in a fully developed turbulent boundary layer at outer velocity of 10m/s.