Analytic solutions of unstable interfaces for all density ratios in axisymmetric flows

An interface between two fluids subject to an external force is hydrodynamically unstable. We extend the Layzer-type potential flow model for unstable interfaces to the system of finite density ratio in axially symmetric geometry and derive analytic solutions for growth rates of unstable interfaces over all times. The analytic expressions for bubble growth rates at finite times are given for arbitrary Atwood number. Predictions of the analytic solutions for growth rates are in excellent agreements with numerical results.