冰盖下水流流动的掺混特性

Turbulent mixing characteristics of ice-covered river flow

本文采用k ε紊流模型建立了冰盖流及物质输移的垂向二维数值模型,对封冻河道水流的垂向掺混特性及水中冰在冰盖下的输移规律进行了研究。研究结果表明,冰盖下水流纵向流速在流动核心部分较为均匀,并不遵循对数分布规律;沿水深水流紊动粘性系数并没有出现为零现象,并当上下边壁粗糙相近时,在水深中部达到最大:位于不同水深位置的水中冰进入封冻河道时,在冰盖下有不同的输移规律,水深中部水中冰的最大浓度值降低速率及扩散范围相对较大。研究结果揭示了冰盖对水流流动及垂向掺混的影响。

The K-ε turbulence model is applied to establish the 2-D numerical model for studying vertical mixing characteristics of flow in ice-covered river and transportation of frazil-ice in water. It is found that the profile of longitudinal velocity is relatively uniform in the flow core and the distribution of velocity deviates from the logarithmic law. The calculated result shows no zero viscosity point occurred to the turbulent viscosity distribution along the depth. The frazil ices entering the ice-covered section from different depths of the river exhibit different transportation laws.