Numerical Simulations Of Three Dimensional Current Coupled With Wave In Coastal Regions And Its Application To The Movement Of Suspension

The coastal and estuary regions are of great economic significance to mankind, where there are kinds of human activities. Since they are interfaces of land and sea, the interaction of hydrodynamic factors here are very complex. Besides, because of the exploitation of coastal source, the environment here is brittle. People take more regard to the coastal environment in recent years, such as the diffusion of suspension. And the coastal environment is closely linked with hydrodynamic factors, so we have to study these factors. On account of the restriction of observation, it is necessary to develop numerical model. And along with the advancement of basic theories and computer, it is possible to use numerical model to forecast the hydrodynamic factors in coastal regions.In this dissertation, firstly, the module for depth-dependent radiation stresses is compiled with FORTRAN and is introduced into COHERENS-Coupled Hydrodynamical Ecological Model for Regional and Shelf Seas. Secondly, a three dimensional current model for Rongxi port is setup with the combination of COHERENS, and SWAN-Simulating WAves Nearshore, and it can be used to simulate the 3-D current coupled with wave. Thirdly, the result is compared with investigation data to prove the modified COHERENS. Lastly, the model is used to simulate the movement of sediment near Dayu and the diffusion of contamination around Dongjiakou. The major conclusions in this dissertation are shown as following:â… ,The coupling of wave should be took into account in the study of current in coastal zone, especially at the time of high tide and low tide, the wave-induced current can't be ignored. Thereby, it is necessary to use the coupled wave-current model to forecast the diffusion and the transportation of suspension at seashore.â…¡,The coupling of current with wave is influenced by the coastal water depth. When the depth is small, waves transform acutely because of shoaling, breaking, and reflection, etc., and the grads of radiation stresses is great as a result, so the currents vary due to the coupling of current with wave. Otherwise, When the depth is great, waves transform small because of shoaling, breaking, and reflection, etc., and the grads of radiation stresses is little as a result, so the currents do not change much.â…¢,In deep water, radiation stresses change along with the wave period and wave height; and it is reverse in shallow water. At the same site, the vertical profiles of S yy, S xx are almost linear while that of S xy is almost logarithmic. And at the different sites, the upper radiation stresses curve is zigzag.â…£,The wave is influenced mostly by the off shore current, and weekly by the long shore current. But when the velocity of long shore current is large, the dissipation of the wave energy is fast.