Diffraction and reflection of irregular waves in a harbor employing a spectral model

Abstract

The SWAN wave model is widely used in coastal waters and the main focus of this work is on its application in a harbor. Its last released version -SWAN 40.51 -includes an approximation to compute diffraction, however, so far there are few published works that discuss this matter. The performance of the model is therefore investigated in a harbor where reflection and diffraction play a relevant role. To assess its estimates, a phase-resolving Boussinesq wave model is employed as well, together with measurements carried out at a small-scale model of the area behind the breakwater. For irregular, short-crested waves with broad directional spreading, the importance of diffraction is relatively small. On the other hand, reflection of the incident waves is significant, increasing the energy inside the harbor. Nevertheless, the SWAN model does not achieve convergence when it is set to compute diffraction and reflection simultaneously. It is concluded that, for situations typically encountered in harbors, with irregular waves near reflective obstacles, the model should be set without the diffraction option.

Quantification of Swell Energy and Its Impact on Wetlands in a Deltaic Estuary

“…Further, it is difficult to model swell energy in a shallow estuary, such as TB. Where diffraction effects are important, e.g., within a harbor or immediately behind barrier islands, phase-resolving models are typically required (Violante-Carvalho et al 2009). The wave diffraction physics that are associated with swell wave energy transformation in partially sheltered shallow water are only an approximation in the SWAN model.…”

Modeling Penetration of Tide-Influenced Waves in Le Havre Harbor

“…Quantification of wave disturbances within harbor basins is of leading practical interest for authorities in planning, designing and operating construction of coastal structures, regulation of ship routing or dredging of entrance channels. Numerous modeling have been implemented to predict the interaction between waves and harbor structures as part of engineering studies (e.g., Abdellah, 2006;Triatmadja, 2010;Violante-Carvalho et al, 2009). The problem of excess wave agitation throughout the different design and construction phases of new harbor infrastructures is one of the main purpose of these studies (e.g., Chiang, 1988;Stratigaki et al, 2010).…”