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A new formula of recovery factor for non-equilibrium transport of graded suspended sediment in the Middle Yangtze River

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Journal of Mountain Science 2023年第1期20卷 87-100页

作者： LI Lin-lin XIA Jun-qiang ZHOU Mei-rong DENG Shan-shan LI Zhi-wei State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China School of Civil Engineering Architecture and EnvironmentHubei University of TechnologyWuhan430068China

Suspended sediment concentrations in the Middle Yangtze River(MYR)reduced greatly after the Three Gorges Project operation,causing the composition of bed material to coarsen ***,little is known about the non-equilibrium transport of graded suspended sediment owing to different bed material compositions(BMCs)along the MYR,and it is necessary to determine the magnitude of recovery *** the Markov stochastic process in conjunction with the hiding-exposure effect of non-uniform bed-material,a new formula is proposed for calculating the recovery factor including the effect of different BMCs,and it is incorporated into the non-equilibrium transport equation to simulate the recovery processes of suspended load in both sand-gravel bed and sand bed reaches of the *** results show that:(i)the recovery rate of graded sediment concentrations at Zhicheng was slower than that at Shashi during the period 2003-2007;(ii)the mean recovery factors of the coarse,medium,and fine sediment fractions in the ZhichengShashi reach were 0.152,0.0012,and 0.0005,respectively,and the coarse sediment recovered up to the maximum sediment concentration of 0.138 kg/m3over a distance of 15 km;and(iii)the results of the new formula that can consider the effect of bed material composition are in general agreement with the field observations,and the spatial and temporal delay effects are inversely related to particle size and ***,the BMC effect on the nonequilibrium sediment transport in different reaches of the MYR needs to be considered for higher simulation accuracy.

关键词： non-equilibrium sediment transport bed material composition transition probability recovery factor Middle Yangtze River

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EFFECT OF COARSENING OF SURFACE BED MATERIAL ONnon-equilibrium sediment transport PROCESSDURING RIVER DEGRADATION

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International Journal of sediment Research 1999年第2期14卷 275-284页

作者： LIU Jinmei WANG Guangqian WANG Shiqiang (1,2,3 Dept. of hydraulic Eng., Tsinghua University, Beijing 100084, China)

Previous investigations of non-equilibrium and equilibrium sediment transport are analyzed and a two dimensional (longitudinal profile) mathematical model of non-equilibrium sediment transport in river channels with non-uniform bed material is presented in this paper The concept of exchange rate of bed material is introduced, and a very short time step is used in the calculation. The distance for sediment recovering equilibrium for the non-uniform bed material is far longer than that for uniform bed material and the mechanism of the phenomenon is discussed. Because the size of bed material is coarsened, the scouring of sand is far less than that for the initial state and the distance of non-equilibrium sediment transport becomes much longer. A slower exchange rate of bed material then leads to a longer distance of non-equilibrium sediment transport.

关键词： Coarsening of surface bed material non-equilibrium sediment transport Exchange rate of bed material Recovering equilibrium distance

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A two-phase model for fast geomorphic shallow flows

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International Journal of sediment Research 2012年第4期27卷 409-425页

作者： Massimo GRECO Michele IERVOLINO Angelo LEOPARDI Andrea VACCA Dipartimento di Ingegneria Idraulica Geotecnica ed Ambientale-Universita di Napoli “Federico Ⅱ”via Claudio 21-80125 NapoliITALY Prof. Dipartimento di Ingegneria Civile e Meccanica-Universita di Cassino e del Lazio Meridionale via Di Biasio 43-03043 Cassino(FR)ITALY Assis.Prof.Dr. 4. Dipartimento di Ingegneria Civile-Seconda Universita di Napolivia Roma 29-81031 Aversa(CE)ITALY Assoc.Prof.Dr. Dipartimento di Ingegneria Civile-Seconda Universita di Napoli via Roma 29-81031 Aversa(CE)ITALY Assis.Prof.Dr.

The paper introduces a 2D shallow water model based on a two-phase formulation for the analysis of fast geomorphic transients occurring in the context of river *** and momentum conservation principles are separately imposed for both *** model naturally accounts for non-equilibrium solid transport,since neither instantaneous adaptation hypothesis nor any lag equation is employed to represent sediment *** hyperbolic character of the proposed model is shown to be preserved independently on the flow *** from numerical simulations of both 1D and 2D test-cases are compared with literature experimental data and with available numerical solutions.

关键词： Morphodynamic model non-equilibrium sediment transport Two-phase shallow-water model Eigenvalues analysis Dam-break flows

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Determination of recovery factor for simulation of non-equilibrium sedimentation in reservoir

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International Journal of sediment Research 2015年第1期30卷 68-73页

作者： Jungkyu AHN ChihTed YANG Civil and Environmental Engineering Department Seoul National University Hydroscience and Training Center Civil and Environmental Engineering DepartmentColorado State University

It is generally acceptable to assume that bed material load is equal to sediment transport capacity,if the exchange between bed and flow occurs ***,for non-equilibrium sediment transport process,there are spatial and temporal delay *** is especially true for reservoir sedimentation *** factor is a coefficient for non-equilibrium sediment *** detemiination of recovery factor can be obtained either experimentally or *** is no consensus on the value of recovery factor in previous *** simulations with a semi-two dimensional sediment transport model,GSTARS4,were conducted in this study using various methods for the determination of recovery factor proposed by previous *** results of a reservoir geometric change were sensitive to the selection of recovery *** was found that the recovery factor as a function of sediment size provided the most reasonable result.A functional relationship between recovery factor and sediment size was determined by comparing simulated and measured reservoir geometric *** sediment has small value of recovery factor.

关键词： non-equilibrium sediment transport Recovery factor GSTARS Reservoir sedimentation sediment transport

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MATHEMATICAL MODEL FOR sediment transport CAPACITY OF HYPERCONCENTRATED FLOW

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International Journal of sediment Research 1994年第1期 63-76页

作者： CAO Ruxuan WU Peian REN Xiaofeng and LIU Mingyun

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ＭＡＴＨＥＭＡＴＩＣＡＬＭＯＤＥＬＦＯＲＳＥＤＩＭＥＮＴＴＲＡＮＳＰＯＲＴＣＡＰＡＣＩＴＹＯＦＨＹＰＥＲＣＯＮＣＥＮＴＲＡＴＥＤＦＬＯＷＩＮＤＩＶＥＲＳＩＯＮＣＡＮＡＬＳ￥ＣＡＯＲｕｘｕａｎ；ＷＵＰｅｉａｎ；ＲＥＮＸｉａｏｆｅｎｇａｎｄＬＩＵＭｉｎｇ...

关键词： non-equilibrium sediment transport limit grain size wash load bed material load homogeneous flow with hyperconcentration of sediment

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A MATHEMATICAL MODEL FOR RESERVOIR sedimentATION AND FLUVIAL PROCESSES

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International Journal of sediment Research 1990年第2期 43-84页

作者： Han Qiwei and He Mingmin (Senior Research Engineers, Dept. of sedimentation Eng. Inst. of Water Conservancy and Hydroelectric Power Research.) (The English text is abridged, altered and edited by Ding Lianzhen)

This paper consists of two parts: mechanism of non-equilibrium transport of non-uniform sediment and its application in the mathematical model. Based on a statistic approach of sediment transport proposed by the authors, a 1 - D equation of non-e- quilibrium transport for various size group of sediment particles is developed. Then equations to predict change of sediment concentration and the corresponding changes in size distribution of suspended load and bed material are also derived. The conception that changes in size distribution are interrelated to sediment-carrying capacity is expounded. These results reveal the essence of sediment transport of non-uniform sediment particles. In the second part a mathematical model incorporating the mentioned equations to compute deposition and scouring in reservoirs as well as the fluvial processes of river channels has been developed. Verification of the model agrees well with field data.

关键词： Mathematical model non-equilibrium sediment transport sediment-carrying capacity Reservoir sedimentation Fluvial process Size distribution Bed material Scouring Deposition Exchange intensity Consolidation of deposit.

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