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A Spectral Wave Model for the Coastal Zone
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1994
Year
Spectral Wave ModelsQuasi-stationery ComputationsCoastal EngineeringEngineeringOcean EngineeringAerospace EngineeringComplex Sea StateWave GroupWave PropagationGeographySurface WaveCoastal ModelingCoastal ZoneOcean Wave ModellingOceanographyWave MotionGrid SuperiorEarth Science
Spectral wave models on a grid outperform conventional ray models and have been applied to deep ocean and shelf seas, but their numerical cost makes them impractical for coastal waters. The authors aim to develop a computationally efficient coastal wave model that can optionally operate as a second‑ or third‑generation model without predefined spectral constraints. They achieve this by eliminating time as an independent variable, employing an unconditionally stable propagation scheme, and testing it on academic and shoal‑crossing cases. The scheme performs well in academic tests, including full wave direction reversal, and yields realistic significant wave heights over a 5 km shoal, demonstrating the importance of planned wave‑wave interactions and wind generation.
Spectral wave models that represent the evolution of the waves on a grid superior in several respects to conventional wave ray models. Spectral models on a grid have been developed for applications in the deep ocean and for shelf seas. However, they are not economically feasible in coastal waters due to numerical limitations. We present the first step in implementation of a version that does not have these limitations. we remove time as an independent variable (reducing the computations to stationery or quasi-stationery computations, which is proper considering the residence time of the waves in the area) and we use an unconditionally stable propagation scheme. The propagation scheme is successfully tested in academic cases, including a case with complete reversal of wave direction. As a preliminary test of propagation in an observed field case, computations are carried out for waves travelling across and around an extended (5 km) shoal. With a limited representation of the bottom induced processes (bottom friction and surf dissipation), realistic results are obtained for the significant wave height. This test also shows the relevance of the planned implementation of the wave-wave interactions (in particular grid interactions) and wind generation. The model is planned to be optionally second-or-third-generation (with or without predefined spectral constraints).