近自由面通气空泡诱导的飞溅水层闭合行为数值模拟OA北大核心CSTPCD

When the distance between a bubble and a free surface is far,the direct interaction between the two interfaces will not occur,showing a weak coupling effect with liquid water as an indirect medium between the interfaces.When a bubble is extremely close to the free surface,their interfaces are fused,showing a strong coupling effect of bubble ventilation,free surface splash and closure.In this paper,numerical simulation is used to investigate the behaviors of the splash closure under the strong coupling effect.Based on the compressible multiphase solver in the framework of open-source software OpenFOAM,the finite volume method and volume of fluid method are used to solve the Navier-Stokes equations and precisely capture the gas?liquid interface,respectively.Numerical results show that the time of external air entering the bubble decreases with the increase of dimensionless standoff distance γ and ambient pressure.The height of splash closure increases with the increase of γ and continuously decreases with the increase of ambient pressure.By analyzing the forces on the splash,we obtain the closure mechanism of the splash induced by a bubble near the free surface.It is mainly driven by the pressure difference between the two sides of the splash and,moreover,the closure time of splash satisfies a-0.92 power law relationship.