一维水域潮波运动的变浅效应

ON THE SHALLOW EFFECT OF THE TIDAL IN ONE-DIMENSIONAL REGION

根据浅水非线性潮波动力学方程，考虑线性变浅的一维水域，采用摄动法求解得到了变浅效应所产生的附加潮彼部分，进而根据所得解的讨论，较详细地揭示了潮波进入浅海后变浅效应的作用下所发生的变化，并得出结论。变浅效应使进入浅海的潮波波速变慢。摩擦效应与变浅效应的相互作用决定了潮被振幅的变化，当变浅效应大于摩擦效应时，潮波振幅增加，且变浅效应越强，潮波振幅增加越大，反之则减小。

Considering nonlinear friction effect, nonlinear tidal waves in shallow water are studied by using one-dimension nonlinear hydrodynamic equations. The water area is supposed as unit wide and the seabed slopes gradually and linearly. The equations are solved with the pertubation method to derive the second order solution,which includes an additional tidal wave (generated by the shallowing effect) besides the shallow nonlinear wave and friction nonlinear wave which are generated after the tidal wave comes into the shallow water area. The additional wave is discussed in detail. Analysis showed this wave acts on the source wave only and has nothing to do with motion characteristics of other waves moving in the. Shallow area. The amplitude of the additional wave is a function of the shallowing coefficient a, friction coefficoent 4 and distance of moving into shallow water x, and has direct ratio relationship with a. The phase of this wave always independs of the seabed slope and changes in the direction of the water depth changing.