Numerical Investigation of Cavitation Scale Effects by Bubble Acoustic
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Published:2018
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This paper focuses on a number of issues related to scale effects based on acoustic cavitation inception. The acoustic pressure emitted by flow bubbles is used to numerically detect the acoustic cavitation inception. The acoustic pressure, the motion as well as the bubble size are calculated by a Lagrange method, which is implemented in the in-house RANS code FreSCo+. In a numerical study on a 2D hydrofoil, various aspects related to water quality, such as e.g. bubble size and bubble concentration, are systematically investigated and analyzed. The inflow velocity and dimension of the investigated body are varied. For a precise definition of acoustic cavitation inception two different criteria are used. They are based on an event rate and an acoustic pressure, which have to be exceeded. The results of the numerical study show that the known cavitation scale effects have a significant influence on the detected cavitation inception number. Based on the analysis of the simulation results for the velocity and body size variation, an extrapolation method is proposed and validated, which is also presented in the paper.