检索结果-南通市图书馆

bedload transport of small rivers in Malaysia

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2014年第4期29卷 481-490页

作者： Zahra ZANGENEH SIRDARI Aminuddin AB GHANI Zorkeflee Abu HASSAN REDAC Universiti Sains MalaysiaEngineering Campus

Numerous time-consuming equations,based on the relationship between the reliability and representativeness of the data utilized in defining variables and constants,require complex parameters to estimate bedload *** this study the easily accessible data including flow discharge,water depth,water surface slope,and surface grain diameter(d50) from small rivers in Malaysia were used to estimate bedload *** programming（GP）and artificial neural network（ANN） models are applied as complementary tools to estimate bed load transport based on a balance between simplicity and accuracy in small *** developed models demonstrate higher performance with an overall accuracy of 97%and 93%for ANN and GP,respectively compared with other traditional methods and empirical equations.

关键词： bedload transport Small rivers Genetic programming Artificial neural network

bedload transport from analytical and turbulence phenomenological perspectives

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2019年第6期34卷 509-530页

作者： Subhasish Dey Sk Zeeshan Ali Ellora Padhi Department of Civil Engineering Indian Institute of Technology Kharagpur Department of Hydraulic Engineering State Key Laboratory of Hydro-Science and EngineeringTsinghua University Physics and Applied Mathematics Unit Indian Statistical Institute Kolkata

In this paper,we present the dynamics of bedload transport from two different *** are the analytical perspective and the turbulence phenomenological *** bedload transport from the analytical perspective,we highlight the systematic advances in the analytical modelling of bedload transport over the *** advances are principally classified into three broad foundations,namely,the deterministic foundation,that includes the bed shear stress concept,stream power concept,force balance concept and bedform concept,and the probabilistic foundation and the turbulence phenomenological foundation of bedload *** bedload transport from the turbulence phenomenological perspective brings into focus the bedload-induced turbulence phenomenology,including the hydrodynamics of mobile-bed and water-worked bed *** also discuss the recent advances in the biofilm-coated bedload ***,conclusion is drawn,highlighting the major research challenges.

关键词： bedload transport Fluvial hydraulics Sediment transport Turbulent flow

Response of bedload transport, submarine topography, and dune internal structures to typhoon processes off Dongfang coast in the Beibu Gulf

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2013年第4期32卷 27-40页

作者： MA Xiaochuan YAN Jun FAN Fengxin YAO Ping Key Laboratory of Marine Geology and Environment Institute of Oceanology Chinese Academy of Sciences University of Chinese Academy of Sciences Zhanjiang Branch of China National Offshore Oil Corporation

bedload sediment transport was estimated by the SEDTRANS96 model based on three-day hydrodynamics data obtained off the Dongfang coast in the Beibu Gulf during Typhoon Ketsana in September 2009. Bed- forms on the sea floor off the Dongfang coast and internal structures of a typical dune were interpreted to evaluate storm influences on individual dunes and the dune field. Results indicated that flow forcings and related bedload transport were both strengthened significantly due to Typhoon Ketsana. The measurements and modeling results, which mainly included three different stages, presented noticeable phasic variation. The three stages were dominated by tidal current （Period I）, tidal current combined with wind-induced waves （Period II）, and swells combined with tidal current and seaward flows （Period III）. This phasic varia- tion could be a common trait of hydrodynamics due to typhoons moving westwardly to the south of Hainan Island and Beibu Gulf in South China Sea. Results indicated that the maximum bedioad transport rate for every burst in Period III was almost 100 times larger than that in Period I and was ten times larger than that in Period II. However, the short-term increase in bedload transport induced by storms like Ketsana did not change the long-term evolution of dune morphology. Evidence was given by the internal structures of a typical dune, which revealed renewed modification under subsequent moderate conditions after storm ero- sion. Instead, storms may influence at different scales and regional allocation of sand dunes in some large areas because changes of the sea floor in large scales can hardly be recovered. More surveys during and after storm passage are also needed to document the level of positive contribution to forward migration.

关键词： typhoon bedload transport sand dune internal structure Beibu Gulf

维普期刊数据库

The quantity of sand fraction sediment in reservoirs as the basis of an assessment of the bedload transport from a reservoir catchment

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2018年第4期33卷 385-394页

作者： Szczepan Ludwik Dabkowski Lukasz Bak Department of Water Quality Institute of Technology and Life Sciences Department of Geotechnics Geomatics and Waste Management Kielce University of Technology

A knowledge of the quantity of the sand fraction in the sediments deposited in reservoirs makes it easier to determine the bedload transport, which is a rarely measured parameter. The current study discusses the results of investigations into the siltation and physical properties of sediment in two small reservoirs located in the southeastern part of Poland. Also, the quantity of the bedload sand fraction was *** estimation of the reservoir capacity loss after t years of operation was based on hydroacoustic measurements. The sediment density, organic matter content, and granulometric composition were evaluated by means of investigations and analyses of bottom sediment core samples. The interpolation of the parameters describing the sediment properties was done using the Kriging method. The analyses indicate that 10.80 thousand m3of sediment were deposited into the Zalew Kielecki Reservoir in the years 2004-2015. Their overall mass was 7320 t, of which sand fraction sediments constituted 39.7%.Between the years 2004 and 2014, the Umer Reservoir retained 11.79 thousand m3of sediment having a mass of 7200 t, of which sand fraction constituted 34.6%.

关键词： Reservoir Sedimentation Bottom sediment properties bedload transport Bathymetry

Mechanism of collision model for bedload transport

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2021年第5期36卷 577-581页

作者： Chenwei Zhao State Key Laboratory of Hydro-science and Engineering Department of Hydraulic Engineering Tsinghua University

The current study introduces a new particleeparticle collision model as well as a classical particleewall collision model to simulate the process of bedload transport. Large eddy simulation and two-way coupling Lagrangian pointeparticle models also are applied. Flow conditions for all simulations are done based on previous experiments and four comparison cases are studied. The bedload function result obtained using this model agrees with the previous studies, which proves that the model is reasonable and effective in dealing with bedload transport in turbulent flow. Otherwise, failure to consider the particleeparticle collision, Basset force, or Saffman lift force in the model lead to underestimating the bedload transport rate.

关键词： bedload transport Collision model Lagrangian point-particle model Turbulent flow

bedload transport in channel bends

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 1995年第1期 101-107页

作者：王平义方铎吴持恭 Chengdu 610065 Chengdu University of Science and Technology China State Key Laboratory of High Speed Hydraulics

Considering changes of bedforra dimensions, the expression of the boundary shear stress responsible for sediment transport is obtained. Then, this expression is used in the Yalin bedload equation to deduce a formula of the bedload transport suitable for channel bends. This formula is proved by experimental data, and laws of sediment transport are analyzed. Results show good agreement between observed bedload transport and predicted one.

关键词： bedload transport channel bends bed form.

EXPERIMENTAL STUDY OF bedload transport IN UNSTEADY OPEN-CHANNEL FLOW

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Sediment Research 1997年第3期 63-71页

作者： T.SONG Post-Doctoral Fellow, School of Civil and Structural Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798. Presently, Civil Engineer, Engineering Depatment, Technology Division, Maritime and Port Authority of Singapore.

Experiments are performed to study bedload transport in both steady uniform and unsteady open-channel flows. Data of Steady uniform flow fit well with the existing formula in the literature. If the formula for sediment transport in a uniform flow is used to predict the bedload transport rate in unsteady flow, the calculated and the measured bedload transport rates are different. For the runs with predominately accelerating flow, the calculated sediment transport rate is smaller than the measured one, while for the runs with predominately decelerating flow, the calculated sediment transport rate is much larger than the measured one. Further analysis shows that if the flow intensity is calculated using the measured friction velocity instead of the bed slope, the calculated bedload transport rate using the formula for uniform flow agrees reasonably well with the measured one.

关键词： Unsteady flow Friction velocity bedload transport ADVP

ASSESSMENT OF BED-LOAD PREDICTORS BASED ON SAMPLING IN A GRAVEL BED RIVER

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2012年第1期24卷 145-151页

作者： HADDADCHI Arman OMID Mohammad H. DEHGHANI Amir A. School of Environment Griffith UniversityNathanQld 4111Australia Department of Irrigation and Reclamation Engineering University of TehranTehranIran Department of Irrigation Engineering Golestan Agriculture and Natural Resources UniversityGorganIran

bedload transport in alluvial channels has been extensively studied and different equations based on field and/or experimental data have been *** of bed-load transport rate using different equations results in wide ranges which are not always *** this study,some of the universal bedload predictors were evaluated with measured load by a Helley-Smith sampler in the Node River,a gravel bed river in the northeast part of *** 19 sets of data,14 series of data were used to evaluate the bed-load transport *** results show that the equations presented by Van Rijn,Meyer-Peter and Mueller,and Ackers and White may adequately predict bedload transport in the range of field data.

关键词： bedload transport gravel bed river bed-load sampling Gorgan-Iran

维普期刊数据库

Numerical modeling of bedload and suspended load contributions to morphological evolution of the Seine Estuary(France)

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2021年第6期36卷 723-735页

作者： Baptiste Mengual Pierre Le Hir Aurélie Rivier Matthieu Caillaud Florent Grasso IFREMER DYNECO/DHYSED Laboratory Centre de Bretagne UMR 7266 LIENSs CNRS-La Rochelle University IRSN (Institut de Radioprotection et de S?reté Nucléaire) PRP-ENV/SERIS/LRC Laboratory

This numerical modeling study(i) assesses the influence of the sediment erosion process on the sediment dynamics and subsequent morphological changes of a mixed-sediment environment, the macrotidal Seine estuary, when non-cohesive particles are dominant within bed mixtures(non-cohesive regime), and(ii) investigates respective contributions of bedload and suspended load in these dynamics.A three dimensional(3 D) process-based morphodynamic model was set up and run under realistic forcings(including tide, waves, wind, and river discharge) during a 1-year period. Applying erosion homogeneously to bed sediment in the non-cohesive regime, i.e., average erosion parameters in the erosion law(especially the erodibility parameter, E0), leads to higher resuspension of fine sediment due to the presence of coarser fractions within mixtures, compared to the case of an independent treatment of erosion for each sediment class. This results in more pronounced horizontal sediment flux(two-fold increase for sand, +30% for mud) and erosion/deposition patterns(up to a two-fold increase in erosion over shoals, generally associated with some coarsening of bed sediment). Compared to observed bathymetric changes, more relevant erosion/deposition patterns are derived from the model when independent resuspension fluxes are considered in the non-cohesive regime. These results suggest that this kind of approach may be more relevant when local grain-size distributions become heterogeneous and multimodal for non-cohesive particles. bedload transport appears to be a non-dominant but significant contributor to the sediment dynamics of the Seine Estuary mouth. The residual bedload flux represents, on average, between 17 and 38% of the suspended sand flux, its contribution generally increasing when bed sediment becomes coarser(can become dominant at specific locations). The average orientation of residual fluxes and erosion/deposition patterns caused by bedload generally follow those resulting from

关键词： Non-cohesive sand-mud mixtures Erosion Suspended sediment transport bedload transport Morphodynamics Seine Estuary