Effects of offshore fringing reefs on the transient harbor resonance excited by solitary waves

Abstract

In this article, effects of the variation of the offshore reef topography on the transient resonance induced by solitary waves with various wave heights are first investigated. The transient resonance is simulated by a fully nonlinear Boussinesq model, FUNWAVE-TVD. This paper focuses on investigating how the variations of the plane reef-face slope, the reef-ridge width, the lagoon width and the reef-face profile shape affect the wave energy distribution, the total wave energy and the maximum oscillation (runup) inside the harbor. Results indicate that all of the uniformity of the wave energy distribution, the total wave energy and the amplification factor of the incident solitary wave (defined as the ratio of the maximum runup to the incident wave height) are shown to gradually decrease with the plane reef-face slope. For the other three topographical parameters (i.e., the reef-ridge width, the lagoon width and the reef-face profile shape), their influences on the resonant wave parameters inside the harbor becomes more complicated. Not all of the resonant wave parameters inside the harbor (i.e., the uniformity of the wave energy distribution, the total wave energy and the amplification factor of the incident solitary wave) present monotonic changes with these three topographical parameters.