湟水与黄河交汇区水力特性数值模拟

Hydrodynamic properties observed at the confluence of the Huangshui River and the Yellow River

河流交汇区在流域系统治理中发挥着控制节点作用。为探究中国西北地区典型Y型天然河流交汇区的水动力特性,以湟水与黄河交汇区为例,构建交汇区紊动水流二维水动力数学模型进行数值模拟研究。结果表明:湟水与黄河交汇区存在典型的高流速区,且其位置和大小与汇流比有关;交汇区在各水文条件下均未形成明显的水流分离区;受干流顶托影响,支流入汇口左右岸会出现反方向回流区,沿水流方向呈翼状贴合壁面分布,其形态随汇流比发生变化。交汇区水流紊动能较大的区域分布在水流剪切层和下游右岸,在各水文时期,随着汇流比增大,剪切层紊动能减小;随着干流流速增大,交汇区下游右岸紊动能增大。本研究可为该交汇区及下游的河道治理、水环境保护及防洪减灾等提供理论基础。

The confluence of rivers plays a pivotal role in managing river basin systems.This study focuses on the hydrodynamic characteristics of the Huangshui River and Yellow River confluence in Northwest China,utilizing a 2D hydrodynamic mathematical model of turbulent flow.The findings reveal a distinct high-velocity region at the confluence,the location and size of which are influenced by the flow ratio.Despite various hydrological scenarios,no significant water flow separation zones form at the confluence.The presence of a main stream causes a flowback area on the left and right banks of the tributary inlet,adopting a wing-shaped distribution along the flow direction.The shape of this area varies with the flow ratio.Turbulent energy concentrates in the shear layer and downstream right bank of the confluence.As the flow ratio increases,turbulent energy diminishes in the shear layer but increases in the downstream right bank.These findings offer a theoretical foundation for river management,water environmental protection,and flood control at river confluences and downstream areas.