Numerical Simulation and Characteristic Analysis of Water Entry Cavitation in Limited-Domain Water

Abstract Structural water entry remains a significant issue in fluid mechanics. Technological advancements and the diversification of application scenarios have introduced complex environmental boundaries, including irregular fluid and limited-domain boundaries, which are encountered during water entry. This study employs the Eulerian finite element method to simulate fluid dynamics and applies an improved immersed boundary method to address problems involving fluid–structure interaction interfaces. A coupled numerical model for structural water entry in limited-domain water is developed. Initially, a theory of water entry cavitation is derived, and the approximate range of boundary effects is determined. Results of pressure regulation experiments show that the numerical model fully demonstrates the numerical algorithm’s effectiveness. Therefore, numerical methods are used in comprehensively analyzing the effects of structural size, water domain size, and water entry speed. Modifications to these factors can alter cavitation evolution characteristics, influencing a structure’s motion state by qualitatively revealing the physical mechanisms of the process through the evolution of free surfaces, speed attenuation, and acceleration evolution at varying parameters. The findings provide valuable technical support for future navigation design.