Aerodynamic pressure reconstruction on generic surfaces from robotic PIV measurements

Abstract

A multi-model method for static pressure evaluations based on 3D PTV data is presented. The volumetric measurement domain is partitioned into an irrotational part where pressure is evaluated in a point-wise manner through Bernoulli’s equation, and a rotational domain where the pressure gradient is spatially integrated. In a third step, the field pressure is mapped onto the solid surface of the object. The method is first assessed on the flow around a 15 cm diameter sphere at 10 m/s. A good agreement is observed for the surface pressure prior to flow separation. Discrepancies in the order of 0.1 to 0.2 Cp are found towards the separated wake region. There is little dependency on spatial resolution, as long as the ensemble averaging cell remains below 50% of the local radius of curvature of the object. The potential of the method to address generic three-dimensional problems of higher geometrical complexity is demonstrated for the time-averaged flow field around a full-scale cyclist, within a 2 m3 measurement domain. The proposed combination of the multi-model pressure evaluation with robotic PIV enables surface pressure measurements in the low-speed flow regime, for unprecedented aerodynamic analysis otherwise possible only by massive instrumentation of the test model with surface pressure taps.