Relationship between bed shear stress and suspended sediment concentration: annular flume experiments

2011 ◽  
Vol 26 (4) ◽  
pp. 513-523 ◽  
Author(s):  
Yunwei WANG ◽  
Qian YU ◽  
Shu GAO
Keyword(s):  
Shear Stress ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Bed Shear Stress ◽  
Flume Experiments ◽  
Annular Flume

Dynamics of Suspended Sediments Related to Fine Particles in Lower Mekong River

2013 ◽  
Vol 446-447 ◽  
pp. 1528-1533
Author(s):  
Sarunya Promkotra
Keyword(s):  
Shear Stress ◽  
Flow Velocity ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Fine Particles ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Mekong River ◽  
Fall Velocity ◽  
Stream Discharge

Analytical results are considered the factors of suspended sediment concentration, fall velocity, dimensionless shear stress, transportation rate and stream discharge. As a result of suspended sediments of Loei, Huang and Mekong River, fine particles account for the applicability in sediment deposits. Floating suspended sediments explicit more clay minerals than suspended sediments. Suspended sediment concentration (SSC) in the estuarine of Loei River and Huang River are moderately less than Mekong River. Flow directions of the interconnected rivers to the mainstream-Mekong River lead to the quantity of SSC. Sediment concentrations attain to the dynamic response. Dimensionless shear stress relates to shear velocity, geometry and grain size of particles, and difference of flow velocity. This shear stress is directly comparative to flow velocity and clay mineral concentrations. The transport rate involves in the flow velocity, SSC and depth of the river. Moreover, stream discharge can be presumed by the geometry of the river and topography of sampling locations.

The effects of suspended sediment concentration on turbulence in an annular flume

2006 ◽  
Vol 40 (4) ◽  
pp. 555-565 ◽  
Author(s):  
Danielle Cloutier ◽  
Magali N. LeCouturier ◽  
Carl L. Amos ◽  
Phil R. Hill
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Annular Flume

scholarly journals Investigation of Ship-Induced Hydrodynamics and Sediment Suspension in a Heavy Shipping Traffic Waterway

2020 ◽  
Vol 8 (6) ◽  
pp. 424
Author(s):  
Lilei Mao ◽  
Yimei Chen
Keyword(s):  
Shear Stress ◽  
Flow Velocity ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Wave Structure ◽  
Sediment Concentration ◽  
Secondary Wave ◽  
Sediment Suspension ◽  
Bottom Shear Stress ◽  
Shipping Traffic

In order to investigate the complex hydrodynamics and associated sediment movement resulting from the ship passages in heavy shipping traffic waterways, field measurements were performed in a heavy shipping traffic waterway. Based on the collected waves, flow velocity and water turbidity data, the analyses of the ship-induced hydrodynamics and associated sediment suspension phenomena were conducted. The low-frequency primary wave and high-frequency secondary wave were more pronounced for a barge and yacht in the wave structure, respectively, and contributed more to the flow velocity fluctuations and the bottom shear stress. The ship-induced bottom shear stress can cause significant suspended sediment concentration increase, and there is a correlation between the maximum suspended sediment concentration and maximum ship-induced drawdown height, which can provide a reference for the waterway management.

scholarly journals COUPLED WAVE-BED DYNAMICS, ATCHAFALAYA SHELF, LOUISIANA

2012 ◽  
Vol 1 (33) ◽  
pp. 116
Author(s):  
Cihan Sahin ◽  
Ilgar Safak ◽  
Alexandru Sheremet
Keyword(s):  
Shear Stress ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Critical Shear Stress ◽  
Flow Characteristics ◽  
Sediment Concentration ◽  
Density Variation ◽  
Acoustic Backscatter ◽  
Concentration Profiles ◽  
Fluid Mud

Observations of waves, currents, suspended sediment concentration and acoustic backscatter are used to re-investigate the interaction between the combined wave-current flow and cohesive sediments on the muddy Atchafalaya inner shelf. Observations support the previously proposed bed reworking cycle by waves of mobilization and resuspension of bed sediment, erosion, deposition with fluid mud formation and consolidation. Suspended sediment concentration profiles are estimated based on the acoustic backscatter of a current profiler. A one-dimensional vertical bottom boundary model is used to reconstruct the vertical structure of the flow characteristics, and estimate parameters difficult to observe directly, such as bottom shear stress. Estimated bed position, concentration profiles and computed bottom stresses remarkably support the previous findings on the bottom stress-resuspension relation, critical shear stress for erosion and bed density variation throughout a storm.

Fractal dimensions of cohesive sediment during settling in steady state flow with different initial sediment concentrations

2005 ◽  
Vol 32 (4) ◽  
pp. 658-664 ◽  
Author(s):  
M Stone ◽  
B G Krishnappan
Keyword(s):  
Shear Stress ◽  
Steady State ◽  
Suspended Solids ◽  
Fractal Dimensions ◽  
Sediment Concentration ◽  
Cohesive Sediment ◽  
Image Analysis System ◽  
Bed Shear Stress ◽  
Annular Flume ◽  
Over Time

Morphology of particle populations of cohesive sediment were examined during settling experiments in an annular flume with different initial sediment concentrations (200 and 350 mg/L) at constant bed shear stress (0.121 N/m2) using fractal dimensions. The area, longest axis, and perimeter of suspended solids were measured with light microscopy and an image-analysis system to determine three fractal dimensions (D, D1, D2). The ratio between the initial and steady state (time T = 300 min) sediment concentration was 0.54 for both experimental runs and is a function of bed shear stress, not the initial sediment concentration. The fractal dimension D changed from 1.32 at the start of the experiment to 1.36 at steady state, which represents an increase in shape irregularity of larger particles over time compared with smaller particles. At steady state, D1 and D2 were 1.19 and 1.66, respectively. Small increases in D1 and D2 over time indicated a change in morphology towards longer and more elongated particles. The D2 measurements in the present study indicate that differential sedimentation is the predominant flocculation mechanism of cohesive sediments in the flume settling experiments. Fractal dimensions of suspended solids were not significantly different at steady state as a function of initial sediment concentration.Key words: particle morphology, fractal dimensions, cohesive sediment, flocculation, deposition, annular flume.

Modelling Erosion and Deposition of Cohesive Sediments from Hay River, Northwest Territories, Canada

2003 ◽  
Vol 34 (1-2) ◽  
pp. 125-138 ◽  
Author(s):  
David Milburn ◽  
B.G. Krishnappan
Keyword(s):  
Shear Stress ◽  
Northwest Territories ◽  
River Sediment ◽  
Critical Shear Stress ◽  
Cohesive Sediment ◽  
Cohesive Sediments ◽  
Bed Shear Stress ◽  
Flume Experiments ◽  
Annular Flume ◽  
Erosion Processes

A large volume sample of river-bed cohesive sediment and water from Hay River, Northwest Territories, Canada was collected during a spring field program in 2000 as part of a study on under-ice movement of sediment just before breakup. Controlled laboratory experiments were subsequently conducted on the Hay River water/sediments in a rotating annular flume at Burlington, Ontario, Canada to better understand the deposition and erosion processes of cohesive sediment transport. The deposition experiments in the rotating flume confirmed that the Hay River sediment is cohesive and the critical shear stress for deposition and the rates of deposition are a function of bed shear stress and the initial concentration of the sediment in suspension. The erosion experiments provided quantitative data on the critical shear stress for erosion and the rates of erosion as a function of bed shear stress and the age of the sediment deposit. The erosion experiments also indicated that the growth of the biofilm had an influence on the erosion characteristics of the Hay River sediment. Based on the data from the rotating circular flume experiments, a modelling strategy is proposed for calculating the under-ice transport of the cohesive sediments in the Hay River.

scholarly journals The Interplay between Flow Field, Suspended Sediment Concentration, and Net Deposition in a Channel with Flexible Bank Vegetation

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2250 ◽  
Author(s):  
Walter Box ◽  
Kaisa Västilä ◽  
Juha Järvelä
Keyword(s):  
Flow Field ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Main Channel ◽  
Future Research ◽  
Flume Experiments ◽  
Realistic Description ◽  
Optical Turbidity

This paper investigates the interplay between the flow, suspended sediment concentration (SSC), and net deposition at the lateral interface between a main channel and riverbank/floodplain vegetation consisting of emergent flexible woody plants with understory grasses. In a new set of flume experiments, data were collected concurrently on the flow field, SSC, and net deposition using acoustic Doppler velocimeters, optical turbidity sensors, and weight-based sampling. Vegetation largely affected the vertical SSC distributions, both within and near the vegetated areas. The seasonal variation of vegetation properties was important, as the foliage strongly increased lateral mixing of suspended sediments between the unvegetated and vegetated parts of the channel. Foliage increased the reach-scale net deposition and enhanced deposition in the understory grasses at the main channel–vegetation interface. To estimate the seasonal differences caused by foliation, we introduced a new drag ratio approach for describing the SSC difference between the vegetated and unvegetated channel parts. Findings in this study suggest that future research and engineering applications will benefit from a more realistic description of natural plant features, including the reconfiguration of plants and drag by the foliage, to complement and replace existing rigid cylinder approaches.

Neural networks approached for modelling river suspended sediment concentration due to tropical storms

2013 ◽  
Vol 11 (4) ◽  
pp. 457-466
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Time Series Data ◽  
Water Discharge ◽  
Sediment Concentration ◽  
Series Data ◽  
Generalized Regression Neural Network ◽  
Event Based

Artificial neural networks are one of the advanced technologies employed in hydrology modelling. This paper investigates the potential of two algorithm networks, the feed forward backpropagation (BP) and generalized regression neural network (GRNN) in comparison with the classical regression for modelling the event-based suspended sediment concentration at Jiasian diversion weir in Southern Taiwan. For this study, the hourly time series data comprised of water discharge, turbidity and suspended sediment concentration during the storm events in the year of 2002 are taken into account in the models. The statistical performances comparison showed that both BP and GRNN are superior to the classical regression in the weir sediment modelling. Additionally, the turbidity was found to be a dominant input variable over the water discharge for suspended sediment concentration estimation. Statistically, both neural network models can be successfully applied for the event-based suspended sediment concentration modelling in the weir studied herein when few data are available.

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