中文摘要：

一块重力的地里的二附加有限厚度的液体的 Rayleigh-Taylor 不稳定性(RTI ) 的线性生长是调查经分解。在二的上面、中间、更低的接口上为不安联合进化方程成层液体被导出。RTI 和三个接口上的不安的振幅的进化的生长率被解决联合方程获得。有限厚度的液体在中间的接口上减少不安的生长率，这被发现。然而，有限厚度的效果甚至为将引起更严重的 RTI 生长的薄层在不安生长起一个重要作用。最后，在不同起始的条件下面的接口位置的依赖较详细地被讨论。

英文摘要：

The linear growth of Ftayleigh-Taylor instability （FtTI） of two superimposed finite-thickness fluids in a gravita- tional field is investigated analytically. Coupling evolution equations for perturbation on the upper, middle and lower interfaces of the two stratified fluids are derived. The growth rate of the RTI and the evolution of the amplitudes of perturbation on the three interfaces are obtained by solving the coupling equations. It is found that the finite-thickness fluids reduce the growth rate of perturbation on the middle interface. However, the finite-thickness effect plays an important role in perturbation growth even for the thin layers which will cause more severe RTI growth. Finally, the dependence of the interface position under different initial conditions are discussed in some detail.