Analysis of high-speed video data for assessment of the risk of cavitation erosion

Paper i proceeding, 2009

The aim of the paper is to present a further development of the analysis procedure for erosive cavitation developed in the EROCAV observation handbook. The aim of the analysis is to support assessment of the risk of erosion on full scale ship propellers and rudders, based on model testing, and to support optimal design with respect to cavitation erosion as well. A physical transparency of analysis and design is wanted and the paper starts with a review of the physics of cavitation erosion that is the basis for understanding possibilities and limitations of this type of analysis. With the solution of the Rayleigh equation for a collapsing cavity as a basis, principles for plotting of cavity collapses recorded by high-speed video are discussed. The so motivated plotting principle is applied on numerical and experimental data and guidelines for plotting and analysis of cavity collapses are formulated. From selected generic cavitation developments on foils and a propeller it has been possible to formulate general, but still applicable, design principles. Application studies remain to be done. Although the present focus is on experimental data the suggested fully developed analysis and design procedure is supposed to be linked to advanced numerical simulation.