A DISCRETE SPECTRAL EVOLUTION MODEL FOR NONLINEAR WAVES OVER 2D TOPOGRAPHY

摘要

A discrete spectral evolution model is presented suitable for the propagation of multi-directional wave fields over weakly two-dimensional topography. A coupled set of amplitude evolution equations is derived that includes the combined effects of wave-wave and wave-bottom interactions in deep-intermediate water depth. A heuristic extension to shallow water is given that describes quadratic wave-wave interactions without restriction on the resonance mismatch. Comparisons to experimental data demonstrate that the model accurately describes the effects of: 1) wave refraction and diffraction by topography with considerable two-dimensional features, and 2) harmonic generation in focal regions. A full account of the theory, including cubic wave-wave interactions and a rigorous treatment of the shallow water limit is given in Janssen et al. (2004).