河渠分汊段的流速分布与不规则边界处理

The Velocity Distribution and Irregular Boundary Treatment of the Branching River or Channel Reach

本文直接对时均流的三维控制方程组沿深度积分且采用κ—ε双方程模型,建立了一个深度平均的紊流数学模型。数值计算采用有限容积法和SIMPLE程式。对分汊河段不规则边界的处理,本文提出了区域坐标系统法,将整个计算区域分成主道、左汊道及右汊道三个子区域,使每个子区域都具有规则边界,对子区域建立各自独立的坐标系统。迭代时先对于区域分别求解,然后耦合联解。子区域之间通过重叠区相互衔接。计算表明,这一方法精度较高、节省计算时间,且简单、易于实现。应用上述数学模型和数值方法,本文对不对称分汊河段的流场进行了计算,得出了计算区域的流场分布。计算结果比较准确地揭示了流场的内部特征。

Integrating directly the 3-D governing equations of the time-averaged flow and adopting the k-ε turbulence model, a depth-averaged turbulence model is established in this paper. The mathematical model is numerically solved using finite volume method and SIMPLE procedure. Regional Coordinate System(RCS) method is put forward to deal with theirregular boundary. The computational domain is divided into three daughter regions as main channel, left branch and right branch. Each daughter region has regular boundaries and a separate coordinate system is established. The daughter regions are solved respectivley and then coupled each other. The overlapping areas connect the daughter regions. Computation shows that RCS is accurate, simple, economic for computing time and easy to operate. Using the above mentioned mathematical model and numerical method, the flow fields of the nonsymmetrical branching channel has been solved and the distribution of velocity in the computational domain is obtained. The computational results reveal the characteristic of the flow field.