贴体正交曲线坐标系下水流泥沙数学模型的构建与应用

Development and Application of Numerical Models for Flow Motion and Sediment Transport in an Orthogonal Body-fitted Coordinate System

为了研究深圳河河口福田保税区围垦填土占用部分河道对深圳河治理工程防洪能力和河床冲淤变化的影响情况，建立了贴体正交曲线坐标系下的平面二维的深圳河河道-河口-海湾整体水域的水流泥沙数学模型，模型中采用双步全隐有限差分法离散求解水流运动方程，悬沙不平衡输运方程采用三阶 QUIKEST 格式离散后用交错方向法求解。在经实测水文资料验证的基础上，应用数学模型计算了 8 种洪峰流量和河口高潮位组合 4 种围垦填土的挖除方案下深圳河沿程水位和河床冲淤变化，讨论了深圳河治理工程防洪能力降低的程度和近河口段洲滩冲刷以及所造成香港一侧红树林的破坏情况，提出了优化挖除方案。

For study on the influence of the partial occupation of river channel due to the reclamation at the Shenzhen river mouth upon the flood control capacity of the Shenzhen river regulation project and the erosion and/or deposition of river-bed, a two dimensional numerical model of flow motion and sediment transport in a body-fitted coordinate is established and applied to the integral river-estuary-bay water area of Shenzhen region. The Double-Sweep-Implicit finite-difference scheme is adopted to solve the momentum and continuity equations of flow motions. The non-equilibrium suspended sediment transport equation is discretized by the third order QUKISET scheme and solved by the Alternative-Direction-Implicit method. On the basis of good agreements of computation results with field data, the water elevation and the erosion and/or deposition of river-bed along the Shenzhen river are computed under different combinations of hydrometric and topographic conditions. The influence of the partial occupation of river channel due to the reclamation at the Shenzhen river mouth is analyzed, and the destruction of the mangrove owing to the erosion of river-bed near the Shenzhen river estuary is also discussed. Furthermore, the scheme to optimize reclamation is recommended.