DEVELOPMENT AND FIELD VALIDATION OF A 2DH CURVILINEAR STORM IMPACT MODEL

The formulations of the 2DH process-based, nearshore morphological model XBeach were extended to allow for curvilinear grids using a finite volume approach. The formulations were tested for schematic cases such as a circular island and a field validation study was carried out for the case of storm erosion during a construction phase of the soft sea defense of the Maasvlakte-2 extension of Rotterdam port. It was found that the 2D curvilinear version performs significantly better than individual 1D runs. The overall skill of the 2D model for this case can be classified as 'reasonable' while the prediction of the erosion can be classified as 'good'.

An Extended Analytic Solution of Combined Refraction and Diffraction of Long Waves Propagating over Circular Island

An analytic solution of long waves scattering by a cylindrical island mounted on a permeable circular shoal was obtained by solving the linear long wave equation (LWE). The solution is in terms of the Bessel function expressed by complex variables. The present solution is suitable for arbitrary bottom configurations described by a power function with two independent parameters. For the case of the paraboloidal shoal, there exists a singular point (α=2) which can be removed using Frobenius series, whereαis a real constant. The present solution is reduced to Yu and Zhang’s (2003) solution for impermeable circular shoal. The numerical results show some special features of the combined effect of wave refraction and diffraction caused by a porous circular island. The effect of key parameters of the island dimension, the shoal slope, and permeability on wave scattering was discussed based on the analytic solution.