Simulation of acoustic and flexural-gravity waves in ice-covered oceans

We introduce a provably stable, high-order-accurate finite difference method for simulation of acoustic and flexural gravity waves in compressible, inviscid fluids partially covered by a thin elastic layer. Such waves arise when studying ocean wave interactions with floating ice shelves, sea ice, and floating structures. Particular emphasis is on a well-posed interface treatment of the fluid-ice coupling. To ensure numerical stability and efficiency, finite difference approximations based on the summation-by-parts (SBP) framework are combined with a penalty technique (simultaneous approximation term, SAT) to impose the boundary and interface conditions. The resulting SBP-SAT approximations are time integrated with an unconditionally stable finite difference method. Numerical simulations in 2D corroborate the predicted efficiency and stability behaviors. The method can be used in its current form to study transmission of ocean waves and tsunamis through ice shelves, and upon coupling to an elastic half-space beneath the ice and water, to study ice motions associated with long-period seismic surface waves.