Rayleigh-Taylor instability at spherical interfaces of incompressible fluids**Project supported by the National Natural Science Foundation of China (Grant Nos. 11275031, 11475034, 11575033, 11574390, and 11274026) and the National Basic Research Program of China (Grant Nos. 2013CB834100 and 2013CBA01504).

Abstract

Rayleigh-Taylor instability (RTI) of three incompressible fluids with two interfaces in spherical geometry is derived analytically. The growth rate on the two interfaces and the perturbation feedthrough coefficients between two spherical interfaces are derived. For low-mode perturbation, the feedthrough effect from outer interface to inner interface is much more severe than the corresponding planar case, while the feedback from inner interface to the outer interface is smaller than that in planar geometry. The low-mode perturbations lead to the pronounced RTI growth on the inner interface of a spherical shell that are larger than the cylindrical and planar results. It is the low-mode perturbation that results in the difference between the RTI growth in spherical and cylindrical geometry. When the mode number of the perturbation is large enough, the results in cylindrical geometry are recovered.