漫滩恒定明渠水流的三维数值模拟

采用Naot-Rodi代数应力模型(N-R模型),结合非均匀交错网格下的混合有限分析法(HFAM)来计算漫滩水流的三维流动。为了得到稳定的收敛解,作了两点改进:其一为非均匀网格中数值离散的导数项二阶格式的引入;其二为复式断面分块耦合技术的采用。给出了漫滩水流主流速等值线、二次流的断面分布、垂线平均流速的横向分布以及主槽与全断面流量比随相对水深的变化规律。部分结果与实验资料的对比,表明NR模型和HFAM能较好地用于研究漫滩水流流速、流量和水位的关系。

3-D numerical simulation on overbank steady open channel flows in compound channels

The Naot-Rodi algebraic turbulence stress model (N-R model) and the hybrid finite analytic method with staged grid are used to predict the behavior of 3-D overbank flow.In order to get the stable convergence solutions,the two kind measures are taken.The first is to use the correctly derivative scheme in non-uniform grid.The second is to use the multi-block matching method.Numerical tests are carried out for an open channel flow with compound section.The detailed results of main velocity contours,second flow distribution in cross section,lateral velocity distribution for relative water depth with 0.46, depth variation of proportions of flow in channel and floodplams are compared with the experimental data.Some quite reasonable results are obtained.It can be shown that the N-R rmdel with hybridfinite analytic method can be used to predict the relationship between water level and discharges for overbank flow.