Numerical Modeling Of Combined Refraction-Diffraction And Reflection Of Wave

Wave is one of the important dynamic factors in ocean. The effects of waves transformation, refraction, diffration, reflection and breaking are all due to the depth of water, varying topography, bottom friction, obstacles and current as waves proceed from offshore to near shore regions. Some basic parameters which are relevant to the cost of buildings as well as the type of structures are determined by the wave factors since these projects are placed in near shore area, so it is of great importance to study the regularity of wave transforming. Experiences show that it is an effective and feasible way to similate the wave transformation in mathematical ways in real coastal engineering. A practical numerical model of mild-slope equation is developed to describe the wave refraction, diffraction and reflection.An extended hyperbolic mild-slope equation, which can take such terms as wind input, bottom friction and nonlinearity of wave into account, here has been deduced into a parabolic one in the form of a series of governing equations described with complex amplitude. It became a complete wave model when integrated with corresponding physical and imaginary (open) boundaries, and can be solved through the improved Crank-Nicholson or the well known Alternating Direction Implicit (ADI) difference method, both of which can accelerate the convergent speed , expand limitation of the mathematical method and improve the quality of the solution.Several verifications are performed to examine the accuracy of the numerical model of the extended mild-slope equation at simulating wave refraction ,diffraction and reflection on some representative topographies and good agreement has been achieved. Then such a successful model being able to simulate the wave dynamics efficiently has been applied to a reconstruct project of a harbor to evaluate the availability of some critical design data and to judge whether the berth condition is safe enough. In addition , some other projects including a artificial peninsula one have also generated good results and verify the applicability of the model at the same time.