  Cartesian-grid methods in combination with immersed-body and volume-of-fluid
methods are ideally suited for simulating breaking waves around ships. A
surface panelization of the ship hull is used as input to impose body-boundary
conditions on a three-dimensional cartesian grid. The volume-of-fluid portion
of the numerical algorithm is used to capture the free-surface interface,
including the breaking of waves. The numerical scheme is implemented on a
parallel computer. Recent improvements to the numerical scheme are discussed,
including implementation of a new multigrid procedure and conversion to MPI
communication. Numerical predictions are compared to laboratory measurements of
a towed transom-stern model.
