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Diffusion enters into hydrodynamic cavitation
Prof Peter Pelz (Technische Universität Darmstadt, Chair of Fluid Systems, GE)

Diffusion is said to be far too slow for being important in hydrodynamic cavitation. This general statement is wrong when it comes to the initial process of cavitation: nucleation. During nucleation there is a large velocity difference between the bulk flow and surface bounded nuclei resulting in thin diffusion layer and surprisingly high muss flux. Thus, a nucleation frequency in the order of 1 to 10 kHz is feasible. In fact, such high nucleation rate is needed for the evolution of a cavity sheet of realistic length. Diffusion cannot be ignored. It is has become the key in understanding streak, sheet and cloud cavitation