界面张力对Rayleigh-Taylor不稳定性的影响

Effects of surface tension on Rayleigh-Taylor instability

将具有简单速度势的Layzer模型和Zufiria模型推广至非理想流体情况,并分别利用这两种模型研究了界面张力对Rayleigh-Taylor不稳定性的影响.首先得到了两种模型下气泡的渐近速度和渐近曲率的解析表达式;其次系统研究了界面张力对气泡的渐近速度和渐近曲率的影响;最后将两种模型进行了比较,并将气泡的渐近速度和数值模拟进行了比较.研究表明:界面张力压低了气泡的速度,但对曲率没有影响;利用简单速度势的Layzer模型所得的气泡的渐近速度比复杂速度势的Layzer模型的值小,但是比Zufiria模型的值大;当阿特伍德数等于1时,简单速度势的Layzer模型和复杂速度势的Layzer模型给出的结果一致.

In this paper, Layzer＇s model which has a simple velocity potential, and Zufiria＇s model are extended to the case of non-ideal fluids, and the effects of surface tension on Rayleigh-Taylor instability are investigated. Firstly, the analytical expressions for the asymptotic bubble velocity and curvature are obtained in the two models. Secondly, the effects of surface tension on Rayleigh-Taylor instability are studied systematically. Finally, the two models are compared with each other and the comparisons with numerical simulation are made as well. The results indicate that the surface tension depresses the bubble velocity, but does not affect the bubble curvature. The Layzer＇s model with the simple velocity potential gives a smaller bubble velocity than that predicted by the Layzer＇s model with a complex velocity potential. But the bubble velocity predicted by the Layzer＇s model with the simple velocity potential is larger than that obtained by Zufiria＇s model. Both Layzer＇s models lead to the same bubble velocity when the Atwood number is A=I.