Abstract: Cavitation is a general phenomenon in fluid systems．It has an obvious effect on the transient characteristics of the fluid system．Cavitation model is taken into account for simulation of fluid systems，fluid properties such as density and bulk modulus are calculated in different pressures．The analytical models are developed by using the hammer and one-dimension fluid transient theory based on the finite difference method，in consideration of the cavitation，release and collapse of bubbles．The results are much closer to the actual physical process and provide guidance and reference for the design of fluid systems．

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