Numerical study on nonlinear characteristics of Rayleigh-Taylor instability

The research on the nonlinear dynamics of Rayleigh-Taylor (RT) before mainly focused on deducing and measuring the constant penetration velocity of the bubble and had little detailed analysis of the nonlinear dynamic characteristics in the liquid spike region. An accurate numerical simulation of the single-mode RT instability was carried out based on the coupled Level-Set and Volume-of-Fluid (CLSVOF) interface capturing method. The detailed information on the pressure fields and velocity fields was obtained. In addition, the steady-state dynamic characteristics in the nonlinear development stage were analyzed. Simulation results show that a local maximum pressure point which is caused by the horizontal impinging flow with the action of inertial force appears at the root of the spike. The dependence of the different characteristic parameters of the steady flow on the initial perturbation wavelength and the inertial acceleration is determined. This work may extend the relevant classical theories of the low speed jet to the RT instability inducing atomization field.