基于圣维南方程组,根据测压管水头在明渠、承压水流中具有相同的表达形式,实现了自由水面水流、承压水流的统一描述。提出采用三角形子断面法描述伏流非规则封闭断面,进而建立了适用于真实Karst地区明渠伏流交替河道的统一型混合流模型。采用半隐方法离散压力梯度项,使用欧拉-拉格朗日法求解对流项,并使用预测-校正法实现了枝状、环状河网各支汊的耦合求解。以夹岩水库工程为背景,采用2000年水文过程对模型进行了测试,结果表明流量计算误差在1.6%以内。进一步研究了明渠伏流交替河道纵向沿程的流速变化规律以及伏流河段前布置人工隧洞的分流规律。在入流洪峰流量、坝前正常蓄水位的水流条件下,明渠段流速一般在0.25 m/s以下,相比之下,伏流段流速可达1.0~3.0 m/s,有利于伏流过流通道的保持。通过1971—1990年水文过程的模拟,得出大中天桥伏流前的人工隧洞的分流比为40.3%~42.8%,小天桥伏流前的人工隧洞的分流比为76.8%~78.6%。研究成果可为工程建设提供设计依据和技术支撑,具有重要的工程应用价值。
Abstract
Since the piezometer heads in open channels and pressurized waters are of the same expression in Saint-Venant equations, the unified description of free-surface and pressurized mixed flow is obtained. A unified mixed flow model suitable for open channel alternating with sinking stream in real Karst areas is established by describing the irregular closed cross-section of sinking stream with triangular closed subsections. The pressure gradient term is discretized using semi-implicit method, while the advection term is solved by the Eulerian-Lagrangian method, and the coupling of branches in dendritic and loop channel networks is solved by prediction-correction method. The proposed model is checked by using the hydrological process of Jiayan Reservoir in 2000. Results reveal an error of flow calculation within 1.6%. Moreover, the variation rules of velocity along the longitudinal direction of the open channel alternating with sinking stream and the division rules of artificial tunnels in front of the sinking reach are investigated. In the conditions of peak flood inflow and normal water level in front of the dam, the flow velocity in open channel segment is generally smaller than 0.25 m/s, whereas the velocity in sinking stream reaches 1.0-3.0 m/s, which is beneficial to the maintenance of sinking stream. During the simulation of hydrological process from 1971 to 1990, the division ratio of artificial tunnels in front of big-medium sized overbridge is 40.3%-42.8%, and the division ratio of artificial tunnels in front of small overbridge is 76.8%-78.6%.
关键词
明渠 /
伏流 /
混合流 /
水动力学模型 /
Karst地区 /
夹岩水库
Key words
open channel /
sinking stream /
mixed flow /
hydrodynamic model /
Karst area /
Jiayan reservoir
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] BOUSSO S, DAYNOU M, FUAMBA M. Numerical Modeling of Mixed Flows in Storm Water Systems: Critical Review of Literature[J]. Journal of Hydraulic Engineering, 2013, 139(4): 385-396.
[2] CUNGE J A, WEGNER M. Numerical Integration of Barre de Saint-Venant's Flow Equations by Means of Implicit Scheme of Finite Differences[J]. Houille Blanche-Revue Internationale de L'Eau,1964, 19(1):33-39.
[3] VASCONCELOS J G, WRIGHT S J, ROE P L. Improved Simulation of Flow Regime Transition in Sewers: Two-Component Pressure Approach [J]. Journal of Hydraulic Engineering, 2006, 132(6): 553-562.
[4] CASULLI V,STELLING G S.A Semi-implicit Numerical Model for Urban Drainage Systems[J].International Journal for Numerical Methods in Fluids,2013,73(6):600-614.
[5] ZHANG Xiao-feng, HU Yi, WANG Si-qiang, et al. One-dimensional Modelling of Sediment Deposition in Reservoirs with Sinking Streams[J]. Environmental Fluid Mechanics, 2017, 17(4): 755-775.
[6] HU De-chao, LI Song-ping, YAO Shi-ming, et al. A Simple and Unified Linear Solver for Free-surface and Pressurized Mixed Flows in Hydraulic Systems[J]. MDPI Water, 2019, 11(10), doi:10.3390/w11101979.
[7] HU De-chao, ZHANG Hong-wu, ZHONG De-yu. Properties of the Eulerian-Lagrangian Method Using Linear Interpolators in a Three-dimensional Shallow Water Model Using z-level Coordinates[J]. International Journal of Computational Fluid Dynamics, 2009, 23(3):271-284.
[8] CASULLI V, ZANOLLI P. Semi-implicit Numerical Modeling of Nonhydrostatic Free-surface Flows for Environmental Problems[J]. Mathematical and Computer Modelling, 2002, 36(9):1131-1149.
[9] HU De-chao, ZHONG De-yu, WANG Guang-qian, et al. A Semi-implicit Three-dimensional Numerical Model for Non-hydrostatic Pressure Free-surface Flows on an Unstructured, Sigma Grid [J]. International Journal of Sediment Research, 2013, 28(1): 77-89.
[10] HU De-chao, ZHONG De-yu, ZHANG Hong-wu, et al. Prediction-Correction Method for Parallelizing Implicit 2D Hydrodynamic Models I: Scheme[J]. Journal of Hydraulic Engineering, 2015, 141(8), 04015014, doi:10.1061/(ASCE)HY.1943-7900.0001012.
[11] HU De-chao, ZHONG De-yu, ZHU Yong-hui, et al. Prediction-Correction Method for Parallelizing Implicit 2D Hydrodynamic Models II: Application[J]. Journal of Hydraulic Engineering, 2015, 141(8), 06015008, doi:10.1061/(ASCE)HY.1943-7900.0001013.
PDF(3369 KB)
