Nonlinear saturation amplitude of cylindrical Rayleigh–Taylor instability

The nonlinear saturation amplitude (NSA) of the fundamental mode in the classical Rayleigh-Taylor instability with a cylindrical geometry for an arbitrary Atwood number is analytically investigated by considering the nonlinear corrections up to the third order. The analytic results indicate that the effects of the initial radius of the interface (r₀) and the Atwood number (A) play an important role in the NSA of the fundamental mode. The NSA of the fundamental mode first increases gently and then decreases quickly with increasing A. For a given A, the smaller the r₀/λ (λ is the perturbation wavelength), the larger the NSA of the fundamental mode. When r₀/λ is large enough (r₀ λ), the NSA of the fundamental mode is reduced to the prediction in the previous literatures within the framework of the third-order perturbation theory.