Numerical Simulations Of Wave Effects On Tidal Current

Wave and tide are two basic hydrodynamic factors. They play an important role in the coastal exploitation, navigation and management. There are interactions between them. They are in different scales both in spatial and temporal domain. Wave effects on tide can be decomposed into five aspects: wave radiation stress, wave-induced surface and bottom boundary layer, Stokes drifts and Coriolis wave stress. In this paper, in order to investigate wave effects on tidal elevation and current, all the wave effects are added into tidal current equations as additional terms through multi-scales methods. The mainly objects include these parts as follows:Wave effects are parameterized through multi-scale method. Tidal current equations with wave effects are deduced. Dimensional analysis is used on basic equations in order to estimate the quantities of different wave effects. Three computational domains are established from the results to investigate tidal current variations under the different wave effects. The criterions of on which condition each wave effect should be included are set up through the analysis.In two-dimensional condition, vertical structure is not taken account in the simulation. Through vertically integrated, wave effects are summaried as wave radiation stress, wave bottom resistance and Stokes drifts. The simulation is only carried out on the small domain. Tidal elevation and current affected by the wave effects are analyzed in suppositional bathymetry. Nearshore current driven by wave breaking is added into tidal current. From the results, we can conclude that wave effects on tide are mainly represented by tidal current.In three-dimensional conditions, the different wave effects on tidal elevation and current are studied in different conditions. The simulations are carried out on three domains based on the result of dimensional analysis. The following conclusions are made from the results: Vertical structure of tidal current redistribute in the effect of Coriolis wave stresses. The water depth affected by wave is same as "Stokes depth". There are different influences in different position. The effect of Stokes drifts can be represented as additional current on the tidal current. Surface layer is mostly influenced. The influence becomes weak with the increase of water depth. Wave surface and bottom boundary layer is directly related to water particle velocity. The influence of wave surface boundary layer is very little so it could be ignored in computation. The effect of wave bottom boundary layer is increased with total water depth decreased. In the near region, wave radiation stress is the most important factor. Tidal current vary both in the surface and bottom.In the last part, numerical model setup in this paper is applied into Bohai Sea in order to investigate wave effects on tidal in actual sea waters. SW wind is selected through analysis of Bohai Sea wind data. SWAN model is used to calculate wind-wave in Bohai Sea. All the five wave effects are included in order to analyze wave effects on tidal elevation and current.