Vibratory characteristics of erosive cavitation vortices downstream of a fixed leading edge cavity

To identify the distinctive vibratory characteristics of erosive cavitation an investigation program was conducted in the IMHEF High Speed Cavitation Tunnel on a NACA 009 stainlcs~: steel profile equipped with 7 DECER electrochemical cavitation erosion detcctors and high frequency vibration sensors. Forces acting on the profile were inferred from a measured transmissibility function. Above a low threshold value a linear relationship was found between the measured mean square value of acceleration and the average erosion rate on the profile. Erosion vortices were found to be shed away from the main leading edge cavity according to a constant Strouhal number law. Their hydrodynamic erosive intensity of a power dimension, proportional to V^(3/2), is defined. This intensity is linearly related to the measured RMS force and average erosion on the profile for a given set of incidence and sigma values. The erosive efficiency of the cavitating flow however decreases with sigma