２次元SPH法によるクラウドキャビテーションの非定常挙動の数値解析

抄録

Cavitation is an unsteady motion which generates a lot of cavities to form a cloud and presents a repeating process called rebounding of its birth, growth, and collapse. In particular, it is considered that a strong shock wave of pressure is generated associated with the collapse of the cloud and it may cause serious problems such as erosion in fluid machinery. Many numerical studies have been conducted so far to clarify such unsteady behaviors of the cloud, however it is not well understood how the inception of the cavitation cloud may be occurred and how its unsteady behavior can be elucidated in the context of the multiphase flows. In this study, we make a two-dimensional numerical analysis of the multiphase flows for a submerged bubbly water jet injection into still water through a nozzle and then we investigate how the cloud cavitation can be made in this system. In this analysis, we employ the mixture model of liquids and gases to model the bubbly-water jet and we make a numerical analysis of the unsteady multiphase flows in Lagrangian description by utilizing the Smoothed Particle Hydrodynamics method. We finally illustrate a scenario of how the inception of the cloud is occurred and how its unsteady behaviors are made in the context of the multiphase flows.