摘要
河流冲淤平衡时间尺度是河流生态修复研究中需重点关注的问题之一,但在校核河流泥沙冲淤过程的数值模型时,一般仅从水动力要素和冲淤范围、空间分布角度来评价,缺少时间尺度方面的研究。变曲率河道水动力特性和床面形态复杂,为此基于Delft3D建立三维水沙数学模型,模拟了不同曲率河道内泥沙冲淤过程,将模拟结果与已有试验结果进行了比较,在此基础上分析了模型和试验中河道冲淤过程达到平衡所需时间尺度的关系。结果表明,不同曲率弯道情况下,数值模拟结果中弯道水流动力轴线变化趋势、冲淤位置及变化范围与试验实测数据基本吻合,说明模型可精确模拟变曲率河道泥沙冲淤后床面的形态变化;模拟达到床面冲淤平衡所需时间为试验的1.3~4.0倍,这是因为Delft3D软件无法设置泥沙粒径级配分布,采用了均匀沙,临界床面剪切应力与试验不同,且未考虑到河床底部变化引起的糙率实时动态响应和试验观测引起的误差。
The time scale of river scouring and silting balance is one of the issues that need to be paid attention to in the research of river ecological restoration. However, when calibrating the numerical model of the river sediment erosion and deposition process, it is generally only evaluated from the perspective of hydrodynamic elements, erosion and deposition range, and spatial distribution, and there is a lack of research on the time scale. The hydrodynamic characteristics and bed morphology of the variable curvature channel are complex. Therefore, the Delft3 D was used to establish a three-dimensional water and sediment mathematical model to simulate the sediment scouring and silting process in different curvature channels. The results were compared with the existing experimental results. On this basis, the relationship between the time scale required for the equilibrium of the river scouring and silting process in the model and the experiment was analyzed. The results show that in the case of the three curvature bends, the numerical simulation results of the curve’s hydrodynamic axis change trend, scouring and silting position and change range are basically consistent with the experimental data, indicating that the model can accurately simulate the morphological changes of bed surface after sediment erosion and deposition in the variable curvature channel. The simulation time required to reach the bed surface scouring and silting balance is 1.3 to 4.0 times that of the test. This is because the Delft3 D software cannot set the gradation distribution of the sediment particle size, and adopts uniform sand. The critical bed shear stress is different from the experiment, and the real-time dynamic response of the roughness caused by the change of the bottom of the river bed and the error caused by the experimental observation are not considered.
作者
张小雅
任春平
冀雅珍
ZHANG Xiao-ya;REN Chun-ping;JI Ya-zhen(College of Water Resource Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China)
出处
《水电能源科学》
北大核心
2022年第7期49-52,共4页
Water Resources and Power
基金
水利工程安全与仿真国家重点实验室开放基金项目(HESS-2006)
山西省自然科学基金面上项目(202103021224116)
山西省水利厅节约用水管理类项目(20210102)。
