大坝下游河床潜流带温度场的影响因素研究

Influence Factors of Temperature Field in Hyporheic Zone on the Downstream Riverbed of the Dam

基于雷诺平均方程(N-S方程)、k-ω湍流模型,并利用CFD-Fluent及COMSOL Multiphysics软件,构建地下水-地表水耦合模型;通过Morris全局灵敏度分析方法探讨单因素影响及多因素影响下河床潜流带内温度场变化规律。结果表明:河床潜流带的温度场对流速v和水深H较为灵敏,其余依次为沙坡高度h和河床底质渗透系数k;河道水位与河床潜流带的温度场变化呈正相关;多因素共同作用对河床潜流带温度场影响明显,且在沙坡下会出现一个半圆的低温区域。通过对大坝下游河床潜流带的温度场进行影响因素敏感性分析,可对水库下游河流生态治理和修复有一定指导意义。

Based on the Reynolds average equation(N-S equation) and k-ω turbulence model and CFD-fluent and COMSOL Multiphysics software, this paper constructed the groundwater surface water coupling model. Through Morris global sensitivity analysis, this paper discusses the variation law of temperature field in hyporheic zone affected by single factor and multiple factors. The results show that the temperature field of hyporheic zone is sensitive to flow velocity v and water depth H, and the rest are, in turn, the height H of sand slope and the permeability coefficient k of river bed bottom. The water level of river channel is positively correlated with the temperature field of hyporheic zone. The temperature field of hyporheic zone is affected by many factors, and a semicircular low temperature area will appear under the sand slope. Influence factors sensitivity analysis on that temperature field of hyporheic zone of the dam downstream could provide valuable information for the ecological treatment and restoration of the rivers downstream.