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Showing 1 to 20 of 37 for “"Bed shear stress"”.
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Bed shear stress under wave runup on steep slopes
Extensive measurements of swash hydrodynamics and bed shear stress were obtained for surging, collapsing, plunging and spilling swashes, in both medium and prototype scale fixed-bed laboratory wave flumes with steep slopes (1:3 and 1:6, respectively). The hydrodynamics of swash flows were found to …
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Estimation of the bed shear stress in vegetated and bare channels
The shear stress at the bed of a channel influences important benthic processes such as sediment transport. Several methods exist to estimate the bed shear stress in bare channels without vegetation, but most of these are not appropriate for vegetated channels due to the impact of vegetation on the …
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In situ characterization of sediment oxygen demand across the spectrum of non-resuspension to full resuspension with varying bed shear stress
… have addressed the dependence of SOD on near-bed velocity and bed shear stress prior to the point of sediment resuspension, there has been limited research that has attempted to characterize the complex and dynamic phenomenon of resuspended-sediment oxygen demand. To address this issue, a new …
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Horizontal pressure gradient and bed shear stress under double dam-break driven swash and validation of a Reynolds-Averaged Navier-Stokes equations based model
… transport rates are often estimated using bed shear stress as the main hydrodynamic driver. However, the importance of pressure gradients relative to bed shear stress in the swash zone is still poorly known. Thus, it is important to investigate the importance between pressure gradients and …
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Experimental And Analytical Investigations Of Solitary Waves On A Beach
… that govern complex coastal hydrodynamics. The bed shear stress is identified as an important quantity and consequently, a shear plate sensor is developed to make accurate measurements of the bed shear stress. Its size is designed to be small enough to give spatially local measurements and its …
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Experimental Study of Pathogenic Microorganism Resuspension from Mobile Bed Sediment in Irrigational Canals
… particles. The resuspension of pathogens from bed sediment in irrigation canals impairs the quality of overlaying water and can result in the contamination of fresh produces. Sediments are known to be potential reservoirs of pathogenic microorganisms. Pathogens’ concentration in the water is …
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Flow and sediment properties influencing erosion of fine-grained marine sediments : sea floor and laboratory experiments
… by using an in situ flume to erode undisturbed bottom sediments on the sea floor in Buzzards Bay, a shallow marine embayment off the Massachusetts coast. Tte muddy sea floor in that area is characterized by a deposit-feeding infauna that reworks the sediments. Observations made with the in …
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Understanding longitudinal ADCP measurements to determine water velocities for open channel flow
… the interpolated velocities to estimate bed shear stress for a river reach. The first research objective focusing on exploring depth-averaged velocity for locations in a river reach presents interpolated transect and longitudinal velocities and compares them to the known transect and …
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Experimental Investigation of Steady Flows at a Breached Levee
… Number, turbulent kinetic energy (TKE) and bed shear stress are computed from the measured results. Results show that the flow is one-dimensional near the inlet and outlet of the main channel. However, it is three-dimensional near the breach. There is a zone of depression having dimensions …
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Hydromorphological evolution of a restored river; a case study in the Upper River Eden catchment
… transitioning from a run dominated river system. Bed shear stress was investigated across the reach to determine levels of entrainment with the majority of the reach subject to bed shear stress above the critical boundary for entrainment, significantly enhancing the post-restoration channels …
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Modeling and Large Scale Simulations of Thermohaline and Particulate Density Currents
… formation and evolution, flow patterns, and bed shear stress patterns, are visualized and explored in detail. The simulation results are compared throughout the work to previously published experimental data and to laboratory experiments performed for this study and present very good …
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Reach-scale controls of a pool-rapid channel during an extreme flood event : Sabie River, South Africa
… the Cainozoic planar surface, producing a mixed-bedrock-alluvial system draining a semi-arid catchment of 7096 km2. The channel sequences between bedrock outcrops alternating with alluvial features and are influenced by rare, high magnitude flood events, which act as a major control to riparian …
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Hydraulic Characterization of Mounded Gravel Fish Nests: Incipient Motion Criteria and Despiking Acoustic Doppler Velocimeter Data
… chub nest data, multiple methods of finding bed shear stress from velocity vertical profiles are evaluated. Bed shear stress is found over the profile of 26 field nests. The ambient to peak flow stress amplification due to a nest's bed protrusion is found to be a proportion of τ = 1.66τ to …
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Benthic habitats in a tide-swept channel of the Pentland Firth and their potential responses to a tidal energy development
… in-situ data for local hydrodynamics, seabed<br/>structure and epibenthic assemblages. Data from a two-dimensional hydrodynamic model com-plemented in-situ flow data and provided an insight into possible changes to local tidal patterns after the deployment of a tidal array. The study …
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Evolution of a non-cohesive granular bed subject to a succession of erosive turbidity currents
… study the evolution of a non-cohesive granular bed subject to a succession of erosive turbidity currents to evaluate the applicability of a proposed interface model that prescribes a relationship between the bed shear stress and the local bed elevation and local bed slope. This study considered …
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Bedload transport: the effects of particle shape and an investigation of a wide range of transport rates
The effects of particle shape on bedload transport and a wide range of bedload transport rates using both bed subsurface and surface layer based approaches are investigated using fractional transport analysis with a similarity approach. Bedload transport data from a stream containing flat, low …
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High-resolution numerical investigation of hydrodynamics and sediment transport within emergent vegetation canopy
… averaged velocity, turbulent kinetic energy, bed shear stress and turbulence intensity were investigated for increasing Reynolds number of the flow, and it was found that experimental measurements within the gap would be non-representative of flow conditions within the array. Further, a …
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The control of wind and waves on sediment transport asymmetry and the long-term morphological development of estuaries
… through consideration of its influence on bed shear stress, τmax. The decrease in bed shear stress associated with greater water depths is compared to increases owing to the larger fetch that accompanies the increased tidal range and the generally stronger currents associated with larger …
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Hypsometric and geometric controls on hydrodynamics, tidal asymmetry, and sediment connectivity in shallow estuarine systems
… between tidal basin geometry and hypsometry, bed shear stress patterns, tidal velocity- and slack water asymmetry, and hypsometric profile shapes were explored for six shallow microtidal basins of Tauranga Harbour, New Zealand. Model results, obtained from a depth-averaged numerical model …
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Morphodynamics of large anabranching rivers : the case of the Madeira River, Brazil
… and impedes channel-floodplain interactions. Bed shear stress, stream power, and sediment transport are further analyzed and discussed. The hydro-geomorphological features of two anabranching structures, one in reach 2 and one in reach 3, each demonstrates floodplain avulsion …
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