Direct, phase-resolved simulations of large-scale nonlinear ocean wave-fields

We develop and apply a direct phase-resolved simulation capability for large-scale nonlinear ocean wavefield evolution. Unlike phase-averaged models, we directly solve the primitive Euler equation and preserve the phase of the wavefield during its nonlinear evolution. As a result, detailed descriptions of the free surface elevation and the kinematics of the wavefield are obtained Using the direct simulation capability, we investigate the validity and limitations of existing approximate theories and models for the prediction of ocean surface wave statistics under different physical parameters. In particular, with 256 processors on the ERDC Cray XT3, we directly compute the nonlinear evolution of a short-crested (three-dimensional) wavefleld in a domain of 28.7km x 28.7km with evolution time up to 30 minutes, and analyze the occurrence statistics and spatial distribution of rogue waves in the wavefield. The effects of spectral bandwidth and angular spreading on wave statistics are investigated.