Effect of the maximum density ratio between liquid and vapor on cavitating simulation

Abstract

The Filter-Based Model (FBM), which was built into CFX through CFX Expression Language (CEL) and a homogeneous cavitation model were employed to simulate cavitating flow around a 2D Clark-y hydrofoil. The effect of a maximum density ratio between liquid and vapor on sheet and cloud cavitating simulation was investigated. The results show that the maximum density ratio has a significant impact on cavitating simulation. The predicted cavitation with default value 1000 is underestimated compared with experiment. With the increasing of maximum density ratio, the interaction interface between liquid and vapor becomes unstable, accompanying the intermittent shedding of small-scale cavities. The cavity length and vapor volume fraction also increase. When the maximum density is increased to some degree, its effect on cavitation flow calculation becomes unobvious. A smaller maximum density ratio can ensure numerical stability but the result predicted with true density ratio is more accurate, so 20000 is recommended as the value of maximum density ratio in cavitation model to reach an optimum between accuracy and convergence.