基于高速冲刷条件下悬浮通量理论的溯源冲刷模型  

A Retrogressive Erosion Model Based on a Sediment Entrainment Theory at High Flow Velocity

作　　者：宋炜杰 王增辉 齐张辛 李定乾 SONG Wei-jie;WANG Zeng-hui;QI Zhang-xin;LI Ding-qian(College of Water Resources and Architectural Engineering,Northwest Agricultural and Forestry University,Yangling 712100,Shaanxi Province,China)

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《中国农村水利水电》2024年第12期220-225,233,共7页China Rural Water and Hydropower

基　　金：国家自然科学基金资助项目(52279076,U2243238)。

摘　　要：溯源冲刷是常发生于水库或者沉沙池中的一种高速冲刷现象,在短时间内可以清除大量前期淤积物。然而,能够准确预测实际场景下溯源冲刷过程的数学模型却比较少见。因此,基于高速冲刷条件下悬浮通量理论建立了水沙耦合的溯源冲刷模型。通过分析高速冲刷条件下的悬浮通量理论建立关于冲刷速率的非线性方程,提出非线性方程的数值解法进而求得控制方程中的垂向泥沙净通量。溯源冲刷模型采用一维有限体积法离散,采用HLLC近似黎曼算子求解数值通量。利用溯源冲刷模型模拟了1982年阳武河灌区沉沙池非汛期溯源冲刷过程,使用实测水位资料和累计冲沙量资料对模型进行了验证,其中计算水面高程的NSE分别为0.621,0.936,0.973和0.949,模型计算累计冲沙量与实测值的相对误差为1.8%,计算结果表明本文所建立的溯源冲刷模型能够准确的模拟溯源冲刷过程。利用模型研究了进口非恒定流量过程对于冲刷量的影响,结果表明在溯源冲刷过程总水量一定的条件下,通过提高峰值流量并延后峰值流量出现的时间可以获得更好的冲刷效果。Retrogressive erosion is a rapid erosion phenomenon commonly occurring in reservoirs or sedimentation basins,which can swiftly remove substantial amounts of previously accumulated sediment within a short period.However,mathematical models capable of accurately predicting the retrogressive erosion process in real scenarios are relatively scarce.Therefore,this paper establishes a water-sand coupled retrogressive erosion model based on the sediment entrainment theory under high-speed erosion conditions.The sediment entrainment theory under high-speed erosion conditions is analyzed to establish a nonlinear equation about the erosion rate.A numerical solution method to slove the nonlinear equation is proposed to obtain the net vertical sediment flux in the governing equations.The retrogressive erosion model is discretized by the one-dimensional finite volume method and the HLLC approximate Riemann operator is used to solve the numerical fluxes.Using the retrogressive erosion model,the non-flood season retrogressive erosion process of the sedimentation basin in the Yangwu River irrigation district in 1982 was simulated.The model was validated using measured water level data and cumulative sediment erosion data.The NSE values for calculated water surface elevation were 0.621,0.936,0.973,and 0.949,respectively.The relative error between the model-calculated cumulative sediment erosion and the measured values was 1.8%.The calculated results showed that the retrogressive erosion model established in this paper could accurately simulate the retrogressive erosion process.The model was used to investigate the influence of the unsteady inflow process on the amount of retrogressive erosion.The results indicate that under a constant total water volume during the retro‐gressive erosion process,improving the peak flow rate and delaying the occurrence of peak flow can lead to better erosion outcomes.

关 键 词：溯源冲刷 沉沙池 有限体积法 非平衡输沙 数值模拟 

分 类 号：TV146[水利工程—水力学及河流动力学]