沙坑局部含沙水流特性的数值模拟研究

分析了FLUENT流体商业软件用于河流动力学问题研究的难点和可行性,应用混合物模型对存在矩形沙坑的河道分清水和含沙水流2种情况进行了数值模拟并对比分析。计算结果表明:水沙耦合计算模式的混合物模型可以较好地模拟河道中的水沙两相流输移现象;泥沙相对流体的动量影响明显,且降低了收敛速度;泥沙会抑制水流的内部紊动。沙坑内部拐角处会形成涡旋的次生流,造成向上游的溯源冲刷和下游的淤积。

Numerical Simulation of Water Flow and Sand Distribution around Sand-pit

The difficulty and feasibility of applying FLUENT software to river dynamics were analyzed. The mixture model was used to simulate the river with rectangular sand pit in two conditions (clear water and sediment-laden water). Results show that the coupled calculation of the sediment laden water could well simulate the two-phase water-sediment transport in river. The existence of sediment influences the momentum variation of water, reduces the convergence speed of the modeling, and also restrains the turbulence of water. Secondary vortex flow forms at the sand pit corner which will cause scouring towards the upstream and deposit in the downstream.