| The wave in process of propagation to offshore from open sea will become deformed including the shoaling, refraction, diffraction,breaking etc. under the influences of the topography and buildings, resulting in complicated and changeable of the near shore wave field.The submerged breakwaters are the buildings which are widely used to dissipate waves and control erosion for the coastal protection engineering. The submerged breakwaters have two types of submerged porous breakwaters and submerged imporous breakwaters. In recent years, in order to widely use of the submerged breakwaters, the study on the evolution and transformation of the wave propagation over the submerged breakwaters, especially over the porous submerged breakwaters, become more and more valuable.This paper first summarizes the history and situation of the study on the submerged breakwaters and then reviews recent advances in the Boussinesq equations. Under the seabed boundary and initial conditions, the Boussinesq equations fully taking account of dispersivity and nonlinearity are from the simplified Euler equations by adding the higher order term and velocity term. At the same time, the paper relates a new Boussinesq equation which apply the finite differences scheme to discretize and solve. In order to add the stability of numerical model and eliminate the effect of reflection, internal wave generation method is applied and the sponge layers are set at two ends of numerical wave tank for absorbing the wave energy. In this way, the regular wave is generated by linear signal. Combining with the numerical model, evolution and transformation of the wave propagation over the submerged porous and imporous breakwaters is simulated in the numerical and experiment models, the results of wave surface and each order of harmonic in two models are compared, which agree well, and then the rules of wave surface and emergence of each order harmonic are summarized. Further more, by comparing evolution and transformation of the wave propagation over the submerged porous breakwaters and imporous breakwaters, analyzing the differences of wave surface and each order harmonic at the same place, the advantages of the submerged porous breakwaters are showed intuitively. |
