Evolution of a five-hole probe calibration near a wall

Abstract Five-hole probes (5HP) are a common tool for measurements of the velocity in turbomachinery studies. In those applications, the spaces are confined, which drives the probes to get close to walls. The proximity of the wall affects the behavior of the 5HP. The wall-related evolution of the calibration of two hemispheric L-shaped 3D printed five-hole probes is investigated in a low speed wind tunnel. 2D Particle Image Velocimetry (PIV) and pressure measurements were carried out. The wall proximity causes the probe to measure that the flow goes away from the wall whereas the boundary layer causes the probe to feel that the flow direction is towards the wall.