闽江河口潮流数值模拟

Numerical simulation of current of Minjiang Estuary

应用边界拟合坐标系统，解决了闽江河口河道曲折汊道多造成的计算方向与河底走向交角过大的难点；针对闽江河口长宽比相差较大的特点，移植了通常用于河道计算的沿纵向求解大尺度矩阵问题转化为沿横向小尺度矩阵求逆的水流方程求解方法，采用全隐差分格式，使闽江口数模网格步长最小控制在50m左右，时步长达3min，潮位、流场与实测拟合良好。

In this paper, we apply the boundary-fitting coordinate system to surmount the difficulty of the large angle of computationed direction and trend of the riverbed caused by winding and multibranch stream of Minjiang Estuary. Countering the characteristic of the large ratio of length and width of Minjiang Estuary, we adapt the solution method of river course computation for fluent equation which usually converts the large scale vertical matrix problem to finding the inverse small scale matrix to solve our problems. By fully using implicit difference scheme, we control the step-length of net of our mathemetical model by at least 50m,time span by at least 3 min. Numerical simulation of tidal level and flow field concide with our first-hand investigation well.