A horizontal two-dimensional numerical model is developed for estimation of sediment transport and sea bed change around a large circular cylinder under wave action. The wave model is based on an elliptic mild slope equation.The wave-induced current by the gradient of radiation stress is considered and a depth integrated shallow water equation is applied to the calculation of the current. The mass transport velocity and the bed shear stress due to streaming are considered, which are important factors affecting the sediment transport around a structure due to waves, especially in reflective areas. Wave-current interaction is taken into account in the model for computing the bed shear stress. The model is implemented by a finite element method. The results of this model are compared with those from other methods and agree well with experimental data.
The reflection of oblique incident waves from breakwaters with a partially-perforated front wall is investigated. Thefluid domain is divided into two sub-domains and the eigenfunction expansion method is applied to expand velocity poten-tials in each domain. In the eigen-expansion of the velocity potential, evanescent waves are included. Numerical resultsof the present model are compared with experimental data. The effect of porosity, the relative chamber width, the relativewater depth in the wave absorbing chamber and the water depth in front of the structure are discussed.
In this paper, the principle of mirror image is used to transform the problem of wave diffraction from a circular cylinder in front of orthogonal vertical walls into the problem of diffraction of four symmetric incident waves from four symmetrically arranged circular cylinders, and then the eigenfunction expansion of velocity potential and Grafs addition theorem are used to give the analytical solution to the wave diffraction problem. The relation of the total wave force on cylinder to the distance between the cylinder and orthogonal vertical walls and the incidence angle of wave is also studied by numerical computation.
