A Spectral Shallow-water Wave Model with Nonlinear Energy- and Phase-evolution

Abstract

Abstract : Our long-term goal is to provide the international community with the capability to determine the hydro-dynamic regimes of coastal environments (including large-scale catastrophic floodings) at the highest level, both operationally, with open source computer codes supported in the public domain, and scientifically with experimental open source codes. Numerical wave modeling in oceanic and coastal waters is usually based on a phase-averaged approach (spectral models), whereas close to shore, in the surf zone and in harbors, it is usually based on a phase-resolving approach (time domain models). Both approaches can be formulated in terms of the energy and phase spectrum of the waves. In the present project we are developing a model in which both these spectra are computed simultaneously in one model set-up over a wide variety of scales (from the deep ocean to small-scale coastal regions). Implemented on an unstructured geographical grid covering all scales (to allow the required extreme flexibility in spatial resolution), this allows waves to propagate from the ocean, across the shelf into coastal waters, around islands, across tidal flats, through channels and over shoals, into the surf zone and into harbors, but also towards cliffs and into fjords, while fully and simultaneously accounting for all relevant processes of propagation (shoaling, refraction, diffraction, transmission and reflection), generation (by wind), dissipation (white-capping, depth-induced breaking and bottom friction) and wave-wave interaction (triad and quadruplet).