Research On The Practical Numerical Simulating Model System Of Near Shore Wave

Wave is one of the most universal physical phenomena in ocean, which is directly related to the safety of coastal engineering, (such as harbor construction, estuary improvement and coast mudflat protection), and is also closely related to the construction and development of marine transportation, aquiculture and costal company. As a result, it is very important to research the propagation and transformation of wave. Now numerical models are often used to simulate the propagation and transformation of wave. On the basis of the modularization, integration and systematization of several independent mathematical models of predecessors, a numerical model system is developed for the near shore wave simulation, which can be used in the practical engineering. The wave parameters for gate (or ahead of breakwaters) can be determined by employing this system, furthermore, the wave field in harbor (or behind of breakwaters) can also be calculated.The model system is made up of two main sections, the calculating module for shallow water wave transformation, the calculating module for harbor wave diffraction. The latter contains the calculating modules for regular wave diffraction and irregular wave diffraction. Firstly, a numerical model for shallow wave refraction-diffraction is presented under the complex topography condition as the calculating module for shallow water wave transformation, which can take the wind energy and bottom friction into account. This model can be employed to determine the wave parameters for gate of breakwaters. Secondly, a mathematical model for regular wave diffraction is introduced by applying the singularity distribution method solving Helmholtz type mild-slope equation, as the calculating module for regular wave diffraction, which can take into account the boundary reflection. Thirdly, a mathematical model for irregular wave diffraction is established as the calculating module for irregular wave diffraction, which is based on the method of simulating irregular wave diffraction by linear superimposing of constitutive regular wave diffraction on energy, as is recommended by the Code of Hydrology for Sea Harbor. The irregular wave is split on frequency and direction and the constitutive regular wave diffraction coefficient can be obtained by using the calculating module for regular wave diffraction, then irregular wave diffraction coefficient in harbor (or behind the breakwaters) can be acquired by employing the calculating module for irregular wave diffraction.Results of the model system are compared to other mathematical models and physical experiments, which are anastomotic and reasonable. The numerical model system is applied in the calculation of a fishery harbor in Zhejiang province and a fishery harbor in Fujian province. The results obviously demonstrate wave diffraction in harbor on condition of boundary reflection. Distribution of wave field in harbor is relatively appropriate. It indicates that the numerical model system has some practical value in actual engineering.