Field Verification of a Computational Fluid Dynamics Model for Wave Transformation and Breaking in the Surf Zone

The commercial computational fluid dynamics model FLOW-3D (Flow Science, Inc., Santa Fe, N.M.) is used to simulate two-dimensional wave transformation and breaking across a naturally barred beach profile. Fine scale pressures and velocities are computed for a 35.5min period over a two-dimensional beach profile measured during the 1990 Delilah field experiment. The model is driven by observed wave spectra obtained in 8m water depth, and results compared with a cross-shore array of pressure sensors and current meters extending from near the shoreline to beyond the surf zone and the spatial distribution of wave breaking patterns obtained from video data. In the calculations, wave breaking is a natural consequence of the fluid dynamics and does not require the use of empirical formulations or breaking criteria. Good agreement between modeled and observed wave height transformation, mean cross-shore flow, and wave breaking variability suggests that the model can be used as a numerical laboratory to study the wave breaking and dissipation process in detail, and perhaps lead to improved parametrizations for more computationally efficient numerical models.