The development of a finite volume method for modeling sound in coastal ocean environment

The rapid growth of renewable energy from offshore sources has raised concerns that underwater noise from construction and operation of offshore devices may interfere with communication of marine animals. An underwater sound model was developed to simulate sound propagation from marine-hydrokinetic energy (MHK) devices or offshore wind (OSW) energy platforms. Finite volume and finite difference methods were developed to solve the 3D Helmholtz equation of sound propagation in the coastal environment. For the finite volume method, the grid system consists of triangular grids in the horizontal plane and sigma-layers in the vertical dimension. A 3D sparse matrix solver with complex coefficients was formed for solving the resulting acoustic pressure field. The Complex Shifted Laplacian Preconditioner (CSLP) method was applied to solve the matrix system iteratively with MPI parallelization using a high performance cluster. The sound model was then coupled with the Finite Volume Community Ocean Model (FVCOM) for simulating sound propagation generated by human activities in a range-dependent setting, such as offshore wind energy platform construction and tidal stream turbine operations. As a proof of concept, initial validation of the finite difference solver is presented for two coastal wedge problems.