Rotational Stabilization of a Rayleigh-Taylor Unstable Cylindrical Implosion

The collapse of cavities within liquids is of relevance to a number of applications, including magnetized target fusion schemes in which a plasma is compressed by an imploding liquid metal surface. This paper examines the Rayleigh-Taylor (RT) driven growth of perturbations on the surface of an imploding cylindrical liquid shell that compresses a gas-filled cavity. The fast rise in pressure at the point of maximum convergence causes the cavity surface to rapidly decelerate in the direction opposite to the density gradient at the gas-liquid interface, which induces the RT-driven growth of perturbations. This perturbation growth may be suppressed by rotating the liquid shell at a sufficient angular velocity such that the net surface acceleration remains aligned with the interface density gradient throughout the implosion. This paper will examine the effect of fluid rotation on the growth of small and large mode number perturbations using an experimental arrangement that allowed for visualization of the cavity surface. Experiments were performed over a range of initial angular velocities, demonstrating both stabilized and under-stabilized implosions. These results were compared to 3-D simulations of the implosion performed in OpenFOAM.