Experiments on the scaling of tip vortex cavitation inception for elliptical hydrofoils

Cavitation has been a major concern to naval engineers as it induces hydrodynamic noise and vibration of marine propellers in both naval and civilian ships. On typical marine propellers, cavitation begins in tip vortices that trail from the tip of the blades. However, model-scale evaluation of full-scale tip vortex cavitation inception is very difficult due to its strong dependency on nuclei population.

Reynolds number dependence of tip vortex cavitation inception has been studied by many authors. McCormick reported that cavitation inception number, σ_i, varied with a power of Reynolds number, Reⁿ. Although McCormick reported the index n to be 0.35, different values of n were proposed by other researchers.

In the present study, Reynolds number dependence of the tip vortex cavitation inception was investigated for elliptical hydrofoils using cavitation tunnels in Japan and Australia. Inception and dynamics of the cavitating flows were observed using a high speed camera. Nuclei distributions were measured by a Cavitation Susceptibility Meter (CSM).