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1 INTRODUCTION The transport of sediment in rivers with active floodplains is a two-dimensional process because the main channel and the floodplain can have very different transport capacities. Therefore, two-dimensional (2D) models are often used to simulate the streamwise and transverse variations of sediment erosion and deposition. Many 2D numerical models have been presented to simulate sediment transport in floodplains (James, 1985; Pizzuto, 1987; Howard, 1992; Nicholas and Walli… 相似文献
2.
Wenxue LI Senior engineer Institute of Hydraulic Research Yellow River Conservancy Commission Zhengzhou China PU QI Senior engineer. Institute of Hydraulic Research Yellow River Conservancy Commission Zhengzhou China Zanying SUN E 《国际泥沙研究》1997,(3)
LINTRODUCTIONTheYellowforeriswellknownasaheavilysilt-caacingriverintheworld.Haaer-concentratedfloodsoftenoccurinitsmasterstemandaswellasthetriblltaries.ThecharacteristicsofdeformationandsedimellttranSportdifferfromreachtOreach.Duetohighsedimelltconcelltration,StrongfluvialactionandthenatUreofunSteadysedimenttranSPOrt,problemsandabnormalphenomenonareoflencreated.ThelaterbringinimpacttOnoodcontrolOfthelowerreach.Thus,itishelpfultoenhancetheunderstandingofthemotionlawsOfhaer-concentrat… 相似文献
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NUMERICAL SIMULATION OF SEDIMENT RELEASE FROM RESERVOIRS 总被引:1,自引:0,他引:1
A. KHOSROWNEJAD A. A. Salehi NEISHABORI 《国际泥沙研究》2006,21(1):74-88
1 INTRODUCTION Reservoirs sedimentation is a serious problem in many countries, including the I. R. of Iran. Accumulation of sediment deposits decreases worldwide reservoir storage capacity by one percent per year (Mahmood, 1987). The loss of reservoir st… 相似文献
4.
Helmut M. HABERSACK Konrad BOGNER Josef SCHNEIDER Michael BRAUNER Department of Water Management Hydrology Hydraulic Engineering University of Agricultural Sciences Vienna Muthgasse Vienna Austria. Department of Forest and 《国际泥沙研究》2001,16(2)
1 INTRODUCTIONIn Anstria reservoirs are frequentiy multi-purpose schemes, being used for power generation, floodprotechon and for wate suPPly downstream. These reservoirs have some adVerse imPaCts on theenvironment around the reservoir and also on the dOwnstream pat:. in rivers with mean annual discharge above 30 m3ls about 36 % of the total length of l884 lQn isimpounded, and only 35% remains as free flowing sections (Muhar, l992),. flooding has been, and continues to be, a serious pr… 相似文献
5.
UNCERTAINTYANDSENSITIVITYANALYSESOFSEDIMENTTRANSPORTFORMULASKehChiaYEH1andSenLongDENG2ABSTRACTInviewoftherandomcharacterist... 相似文献
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M. A. MEKONNEN B. DARGAHI 《国际泥沙研究》2007,22(3):188-198
The 3D numerical model, ECOMSED (open source code), was used to simulate flow and sediment transport in rivers. The model has a long history of successful applications to oceanic, coastal and estuarine waters. Improvements in the advection scheme, treatment of river roughness parameterization and shear stress partitioning were necessary to reproduce realistic and comparable results in a river application. To account for the dynamics of the mobile bed boundary, a model for the bed load transport was included in the code. The model reproduced observed secondary currents, bed shear stress distribution and erosion-deposition patterns on a curved channel. The model also successfully predicted the general flow patterns and sediment transport characteristics of a 1-km long reach of the River Klar?lven, located in the north of the county of V?rmland, Sweden. 相似文献
7.
Quanxi XU Songsheng CHEN Ming XIONG Shengwei LI Zefang CHEN 《国际泥沙研究》2007,22(3):228-237
The Jialingjiang River basin is one of the main sediment contributing areas in the upper reaches of the Changjiang River. Great changes have taken place in the runoff and sediment discharge in recent years. Comparing the data of 1991-2003 with the data of 1954-1990, the annual runoff of the Jialingjiang River basin decreased by 23 %, and the suspended sediment transport decreased by 74% or 105 million tons. The main factors affecting the reduction include a decrease in rainfall, sediment detention of hydraulic structures, soil and water conservation activities, sedimentation and sand dredging in the river channel. Thorough investigation and analysis of the contribution of each factor to the sediment decrease at Beibei Station was determined for the first time. The following are the contributing percentages for each factor: a decrease in runoff accounted for 32.9%; soil and water conservation measures accounted for 16.4%; sediment detention of hydraulic structures accounted for 30.5%; sedimentation, river channel sand dredging, and other factors accounted for 20.2%. These findings are very important for forecasting the trend of inflow sediment discharge variation. 相似文献
8.
Albert MOLINAS 《国际泥沙研究》2003,18(3)
A new method based on the Transport Capacity Fraction (TCF) concept is proposed to compute the fractional transport rates for nonuniform sediment mixtures in sand-bed channels. The TCF concept is derived from the understanding that the measurements and predictions of bed-material load are more accurate and reliable than the measurements and predictions of fractional loads. First the bed-material load is computed using an appropriate equation, then the fractional transport rates are determined by distributing the bed-material load into size groups through a transport capacity distribution function. For the computation of bed-material loads, the Ackers and White, Engelund and Hansen, and Yang equations are used in this study. Two new transport capacity distribution functions are developed for flows in sand-bed channels. The new expressions presented in this paper account for the sheltering and exposure effects that exist in mixtures. Comparisons with measured data show that the proposed method can signifi 相似文献
9.
ChinaisoneOfthecountrieswhichsufferfromthemostserioussoilerosionintheworld,andthehillyandgullyareasof~PlateauinthemiddlereachesOftheYellowRiverarethemostseriouserosionareainChina.Inthisarea,themainerosivefactorsarerainfallandrunoff.Sometimes,thesedimentyieldinasinglefloodeventcanbe40%oftheannualsedimentload.Therefore,itisveryimPOrtanttostudytheyieldandgraphOfSedimentOfsinglefindevent.Forthispn~,thispaperiswritten.AInongsedimentmodelsforsinglefloodevent,moreandmoreattentionwaspaidtOunitse… 相似文献
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APPLICABILITY OF SEDIMENT TRANSPORT FORMULAS 总被引:3,自引:0,他引:3
Chih Ted YANG Caian HUANG Manager Sedimentation River Hydraulics Group Technical Service Center U.S. Bureau of Reclamation Denver Colorado . Graduate student College of Harbour Waterway Coastal Engineering Hohai University Nanjin 《国际泥沙研究》2001,16(3)
1 INTRODUCTIONThe selection of aPPropriate sediment transport fOrmulas under different flow and sedfornt conditions isimPoftant tO the sedimen tusPort and river morphologic stUdies of a river. There are numrousWlas published in professional joumals and summarized in sediment transPort texthooks. Mosttextbooks shy away from direct comPallsons of the accuracies of transPort formulas. ComPllted resultsbased on differnt transport formulas may differ significanly from each other and from … 相似文献
11.
1 INTRODUCTION TheCirculatingFlow(CF)exhibitssecondaryflowandoccursinnatureandthehydraulicandwatertransportengineering,inwhicht... 相似文献
12.
Hongwei FANG 《国际泥沙研究》2003,18(2)
1 INTRODUCTION With advances in computer technology and numerical methods, three-dimensional (3D) mathematical models for sediment transport are gradually applied more often and for more practical projects of hydraulic engineering. Three-dimensional mathematical river models can describe not only the secondary flow, but also the transport, deposition, and erosion of sediment in the river channel and the flood plain. However, at present the theories of sediment transport are not as well de… 相似文献
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14.
WeimingWU SamS.Y.WANG 《国际泥沙研究》2004,19(4):241-257
The helical flow significantly affects the flow, sediment transport and morphological evolution in curved channels. A semi-empirical formula is proposed to determine the cross-stream distribution of the helical flow intensity in the developed regions of a channel bend. It is then used to evaluate the dispersion terms in the depth-averaged 2-D momentum equations and suspended-load transport equation as well as the bed-load transport angle, thus enhancing the depth-averaged 2-D model to account for the effect of helical flow. The tests in several experimental and field cases show that the enhanced depth-averaged 2-D model can much more reasonably predict the shifting of main flow from inner bank to outer bank, the erosion along outer bank and deposition along inner bank than the depth-averaged 2-D model without considering this effect. 相似文献
15.
TaWei SOONG 《国际泥沙研究》1999,(2)
IINTRODUCTIONLanddevelopmentandlandusepatternsinthewatershedcaninduceincreasedsedimentloadsinriversandstreams.AGREATIllstudy(1982)illustratedthatsedimentyieldsfromagriculturallandcouldbeseveralfoldsmorethanothertypeoflandusesanderosionsources.ThesamestudyalsodemonstratedthatfinesedimentsweretheheaviestportionoftotalsoillossesfromeachtypeoflandusesinthetwelvehydrologicareasitinvestigatedintheUMRS.Thesamecouldbetrueforotheruplandareasalso.Howeverfinesediments,formthewashloadofthestream… 相似文献
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L. YILMAZ Vijay P. SINGH S.K. MISHRA D. D. ADRIAN J. J. SANSALONE Civil Engineering Faculty Hydraulic Division Technical University of Istanbul Maslak Istanbul Turkey 《国际泥沙研究》2002,17(1)
1 INTRODUCTION River erosion is a complex phenomenon. The rate of bank retreat is determined by flow, bed topography, sediment transport, bank properties, and water quality. Prediction of future river planform changes and the knowledge of river erosion and river meandering are required for land use planning in alluvial river valleys and determining locations for bridges and hydraulic structures. The control of riverbank erosion requires prediction of flow and bed features in a meanderin… 相似文献
17.
Zhixian Cao Prot. Dr.-Ing.. Director of Institute of Hydraulic Engineering Tianjin University. Tianjin . China. Wensheng WangSenior Engineer Associate Director of Lower Haihe River Administration Bureau. Ministry of Water Resources. Tianjin 《国际泥沙研究》1997,(3)
I.~ODUCTIONSuspendedsedimenttransportcapacity(SSTC)ofopenchannelflowisoneofthebasicsubjectsinsedimenttransportmechanicsandsedimentationengineeringpractice.Mostexistingformulationsareempiricalandsemiempiricalorrestheavilyonassumptionswhicharenotyetjustified.Thisarisesmostlybecauseofthecomplexityoftheproblem.Forafullydeveloped,in-equilibriumflowinawiderectangularchannel,theSSTCcanbbdeterminedasfollowsor=n:,ty)cab)-dy=Ca'I(l)1I=J4(D)'exp[--V,(n)]'da(2)unwhereCTIsSSTC,uistheaveragedflo… 相似文献
18.
EFFECT OF COARSENING OF SURFACE BED MATERIAL ON NON-EQUILIBRIUM SEDIMENT TRANSPORT PROCESS DURING RIVER DEGRADATION 总被引:2,自引:0,他引:2
1INTRODUCTIONNon-equilibriumsedimenttransportina"at'Uralstreamwithnon-uniformbedmaterialisasubjectofilltensiveresearch.ThesedimentconcentrationmaybenotequaltothetransportcapacityofflowinanalluvialrivedItgraduallyapproachesequilibriumbydegradationoraggradationinalongdistance.usuallyover100kilometers.Thisproblemisofgreatimportancetothepredictionofthedistributionoferosionordepositionalongachannel,especiallyforlargeriversinChina.Scientistsstudiednonequilibriumsedimenttransportandthemainresul… 相似文献
19.
DEPTH-AVERAGE ANALYSIS OF HYSTERESIS BETWEEN FLOW AND SEDIMENT TRANSPORT UNDER UNSTEADY CONDITIONS 总被引:1,自引:0,他引:1
Weiming WU Mustafa ALTINAKAR Sam S. Y. WANG 《国际泥沙研究》2006,21(2):101-112
1 INTRODUCTION Flow and sediment transport in natural rivers are generally unsteady, and exhibit temporal and spatial lags. Traditionally, in most hydraulic engineering problems the unsteady flow and sediment transport are approximately treated as steady … 相似文献
20.
GAO Jianen Senior Engineer North-West Hydro-technical Science Research Institute Yangling Shaanxi China WAN Zhaohui Professor China Institute of Water Resources & Hydropower Research P.O. Box Beijing . China CHEN Zhicong Profe 《国际泥沙研究》1997,(3)
LABRIEFINTRODUCTIONOFRANDUNIRRIGATIONDISTRICTYellowRiverisoneofthemainWaterresourcesinNOrthChina.SincethefiftiesirrigationbydivertingwaterfromtheYellowforerdevelOPssteadily.AstheYdlowforerisaheavilysacmentsladenone,sedimentisdiVertedsimultaneouslywhenwaterisdiverted.HOwtoproperlytreatthedivertedsedimentboomesoneOfthekeyproblemsrestrichngthesustainingdevelOPmentofthCwaterresourcesinthatarea.LongchStanceconvopngsedimentisoneofthemainmeasuresfordealingwiththediVertedsedim… 相似文献