伶仃洋三维流场数值模拟

A Numerical Simulation of the Three-Dimensional Flow Field of Ling Ding Yang

使用σ坐标变换技术，将（ｘ，ｙ，ｚ，ｔ）坐标系中的三维非线性Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程转换成（ｘ，ｙ，ａ，ｔ）坐标系中的方程，采用有限差分方法进行离散求解，用垂向（σ向）积分的连续方程求解水位，用动量方程求解流速垂直结构，在水平方向上使用非交错正方网格，σ向等间距分层，从而建立三维流场数学模型。应用本模型对多口门、多岛屿、地形及岸线复杂的伶洋的枯季、洪季流场进行了数值模拟。将模拟结果与多个水位、流速同步测站的实测资料进行比较，无论是水位、垂线平均流速、流向过程线还是流速的垂向分布形式与量值，二者均吻合较好。根据模拟计算结果，对伶洋流场的平面及空间结构特征进行了分析。

By using d coordinate transformation technique to transform the three-dimensional nonlinear NavierStokes equations in (x, y, z,t) coordinate system into equations in (x, y, a,t) coordinate system, of which finite difference method is adopted to carry out discreteness and solution with non-crossing square grid in horizontal direction and envenly-spacing in d direction, using vertically-integrated(in o direction) continuous equation to get water level,and using momentum equation to get vertical structure of flow velocity, this paper sets up a three-dimensional flow field mathematical model. The present model is employed to carry out a numerical simulation of the dry and flood season)s flow field of Ling Ding Yang(LDY) with many river mouths and water channels, many islands, and complex topography and coastline, the results of which are compared with the measured data of many synchronous water level and flow velocity stations, and good agreement is found between the measured and computed re.sults of both water level, vertically-averaged flow velocity, flow direction and vertical distribution form and magnitute of the flow velocity.In terms of the computed results, the characteristics of plane and space structure of LDY flow field are analysed.