Abstract
A 3D axisymmetric Galerkin boundary integral formulation for modeling the motion of one inviscid fluid enclosed inside another is described. The interface variables are the velocity potential and the normal velocity, and they can be solved for separately, the second linear system being symmetric. The algorithm is validated by comparing with the analytic solutions for a static interior spherical drop, over a range of values for the relative densities D=rho_E/rho_I of exterior and interior fluids, and various boundary conditions. For time dependent simulations utilizing a Level Set method for the interface tracking, the accuracy has been checked by comparing against the known oscillation frequency of the sphere. Pinch-off profiles corresponding to an initial two lobe geometry drop and D=6 are also presented.