scholarly journals Observations of Bedform Migration and Bedload Sediment Transport in Combined Wave‐Current Flows

2019 ◽  
Vol 124 (7) ◽  
pp. 4572-4590 ◽  
Author(s):  
M. E. Wengrove ◽  
D. L. Foster ◽  
T. C. Lippmann ◽  
M. A. de Schipper ◽  
J. Calantoni
Keyword(s):  
Sediment Transport ◽  
Bedload Sediment ◽  
Current Flows

Monitoring bedload sediment transport in a pre-Alpine river: an experimental method

2017 ◽  
Vol 43 ◽  
pp. 57-63 ◽  
Author(s):  
Monica Papini ◽  
Vladislav Ivov Ivanov ◽  
Davide Brambilla ◽  
Diego Arosio ◽  
Laura Longoni
Keyword(s):  
Sediment Transport ◽  
Experimental Method ◽  
Alpine River ◽  
Bedload Sediment

Nearshore Bedload Sediment Transport

2001 ◽  
Author(s):  
Thomas G. Drake
Keyword(s):  
Sediment Transport ◽  
Bedload Sediment

Bottom friction and bedload sediment transport caused by boundary layer streaming beneath random waves

2004 ◽  
Vol 26 (5) ◽  
pp. 183-197 ◽  
Author(s):  
Dag Myrhaug ◽  
Lars Erik Holmedal ◽  
Håvard Rue
Keyword(s):  
Boundary Layer ◽  
Sediment Transport ◽  
Bottom Friction ◽  
Random Waves ◽  
Bedload Sediment

Characterization of Bedload Sediment Transport in High Slope Rivers Using Hydraulic Geometry Theory

2019 ◽  
Author(s):  
Veronica Carrillo ◽  
John Petrie ◽  
Esteban Pacheco ◽  
Luis Timbe ◽  
Felipe Cisneros
Keyword(s):  
Sediment Transport ◽  
Hydraulic Geometry ◽  
High Slope ◽  
Bedload Sediment

Effect of particle shape on bedload sediment transport in case of small particle loading

Meccanica ◽  
2019 ◽  
Vol 55 (2) ◽  
pp. 299-315 ◽  
Author(s):  
Ramandeep Jain ◽  
Silvio Tschisgale ◽  
Jochen Fröhlich
Keyword(s):  
Sediment Transport ◽  
Small Particle ◽  
Particle Shape ◽  
Particle Loading ◽  
Bedload Sediment

scholarly journals Flow dynamics and bedload sediment transport around paired deflectors for fish habitat enhancement: a field study in the Nicolet River

2007 ◽  
Vol 34 (6) ◽  
pp. 761-769 ◽  
Author(s):  
David M Carré ◽  
Pascale M Biron ◽  
Susan J Gaskin
Keyword(s):  
Sediment Transport ◽  
Radio Frequency Identification ◽  
Fish Habitat ◽  
Sediment Traps ◽  
Bedload Transport ◽  
Flow Dynamics ◽  
Left Bank ◽  
Passive Integrated Transponder ◽  
Bedload Sediment ◽  
The Impact

Schemes to restore fish habitat in rivers often involve installing instream structures such as current deflectors to create and maintain riffle-pool sequences. However, there is a lack of field studies on the impact of these structures on flow dynamics and bed topography. The objective of this research is to characterize flow dynamics and sediment transport around paired deflectors used to enhance fish habitat in the Nicolet River, Quebec. Bed and bank topography surveys were taken with a total station, and velocity and bed shear stress estimates were obtained from an acoustic doppler velocimeter. Bedload sediment transport was assessed by two methods: tracer rocks (painted "particles" and passive integrated transponder tags) and sediment traps. Results show marked differences in bedload sediment transport patterns between the left bank and the right bank downstream of the deflectors. This is surprising considering that paired deflectors should produce a relatively symmetrical disruption to the flow field on each side. More high-flow dynamics data during overtopping conditions are required to understand the complex interactions between these instream structures and bedload transport. Key words: stream restoration, pool, bedload transport, radio frequency identification (RFID), passive integrated transponder (PIT) tags, fieldwork, deflectors, fish habitat.

scholarly journals Mechanism of Tsunami-Induced Erosion of Bridge-Abutment Backfill and Its Countermeasures

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3529
Author(s):  
Tomoaki Nakamura ◽  
Chisato Sugiyama ◽  
Yong-Hwan Cho ◽  
Norimi Mizutani
Keyword(s):  
Numerical Analysis ◽  
Sediment Transport ◽  
Numerical Experiments ◽  
Sediment Suspension ◽  
Downstream Side ◽  
Upstream Side ◽  
Bridge Abutment ◽  
Sediment Transportation ◽  
Bedload Sediment ◽  
The Stability

Tsunamis can destroy bridges in coastal areas. Studies have attempted to unravel the mechanism of tsunami-induced damage and develop effective countermeasures against future tsunamis. However, the mechanisms of tsunami-induced erosion of bridge-abutment backfill and its countermeasures have not been studied adequately. This study investigates this topic using numerical analysis. The results show that the tsunami flowing down along the downstream wing of the abutment induces bedload sediment transport on the ogive section of the backfill on the downstream side of the abutment, resulting in the onset of backfill erosion. Sediment suspension and bedload sediment transportation occur when the backfill inside the abutment starts to flow out from below the downstream wing. This leads to subsidence of the backfill at the upstream side of the downstream wing. The subsequent backfill erosion is mainly caused by bedload sediment transport. Numerical experiments on countermeasures show that extending the wings downward can prevent the acceleration of backfill erosion in the presence of the abutment. A combination of multiple countermeasures, including extended wings, would be more effective in maintaining the stability of the abutment after a tsunami. This suggests the application of such countermeasures to actual bridges as an effective countermeasure against backfill erosion.

scholarly journals Observing and modeling bedload sediment transport at the grain-scale

2020 ◽  
Author(s):  
Eric Deal ◽  
Taylor Perron ◽  
Jeremy Venditti ◽  
Qiong Zhang ◽  
Santiago Benavides ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Particle Tracking ◽  
High Speed ◽  
Flume Experiments ◽  
Physical Mechanisms ◽  
Glass Spheres ◽  
Granular Dynamics ◽  
Image Velocimetry ◽  
Laboratory Flume ◽  
Bedload Sediment

<p>Empirical sediment transport models have common characteristics suggestive of the underlying physics, but mechanistic explanations for these characteristics are lacking due to an incomplete understanding of the fundamental physical mechanisms involved. Hydrodynamic interactions at the grain-scale are thought to be key, however, it is a major challenge to either observe or model these processes. In order to improve our understanding of grain-scale dynamics in sediment entrainment and transport we are studying the detailed mechanics of fluid-grain interactions using a combination of laboratory flume experiments, advanced numerical simulations, and granular mechanics theory. </p><p>The flume experiments are conducted with an emphasis on exploring differences and similarities in the behaviour of glass spheres, a common theoretical tool, to naturally sourced river gravel. Using high-speed cameras coupled with computer-vision based particle tracking, we tracked the majority of grains in the grain bed and water column, with 130,000 glass sphere track paths longer than 10 particle diameters. In particular, we introduce a newly developed a machine learning based particle tracking of the natural grains, with 30,000 gravel track paths longer than 10 mean particle diameters. Fluid flow fields are also observed using particle image velocimetry (PIV). We present the comparison of our detailed observations of granular dynamics between spheres and natural gravel, with a focus on how grain shape impacts fluid-grain and grain-grain interactions.</p><p>Using a discrete-element plus Lattice-Boltzmann fluid method (LBM-DEM) we simulate a small portion of the laboratory flume with high temporal and spatial resolution. This method tracks discrete particles interacting with each other through contact laws while mechanically coupled to a dynamic interstitial fluid. We discuss the ability of our simulations to emulate our experiments, the benefits of which are twofold. First, where the simulations work well, we use them to observe grain-scale dynamics that would be difficult or impossible to measure in a laboratory setting or in the field. Second, we learn from situations in which the experiments and simulations diverge, leading to improvements in both the simulations and our understanding of how fluid-grain interactions influence sediment transport.</p>

scholarly journals WAVE-CURRENT INTERACTION, SEDIMENT TRANSPORT AND SEABED EVOLUTION IN THE PIRAQUÊ-AÇU/PIRAQUÊ MIRIM ESTUARY (BRAZIL)

2017 ◽  
pp. 32
Author(s):  
Thais Nunes Coutinho ◽  
Leonardo Carvalho De Jesus ◽  
Julio Tomás Aquije Chacaltana
Keyword(s):  
Sediment Transport ◽  
Gravity Waves ◽  
Morphological Changes ◽  
Morphological Evolution ◽  
Seabed Sediment ◽  
Estuary Mouth ◽  
Sediment Mass ◽  
Current Interaction ◽  
Bedload Sediment ◽  
Seabed Evolution

The medium-term seabed evolution of Piraquê-Açú/Piraquê-Mirim estuary (ES/Brazil) is studied numerically in this work. The hydrodynamics is induced by the tide, the river discharges, and the incident water wave. The wave-tide-current interactions are obtained by coupling the shallow water equations with the radiation stress tensor introduced by Longuet-Higgins & Stewart (1960). In this way, the influence of both the tidal current and the current induced by gravity waves on the sediment transport are taken into account. We utilized the Exner (1925) equation, based on the conservation of seabed sediment mass, to calculate the morphological evolution. Seabed morphological changes are accelerated by introducing a time scale factor. Four bedload sediment transport formulations were tested and compared. We found an excellent agreement when numerical results are compared with currents measured in the upper estuary and with sediment transport rates measured at the river’s mouth when using the Engelund and Hansen (1967) sediment transport formulation. We also found that the main morphological changes occurring at the estuary mouth are due to the action of gravity waves. Between the head and mouth of the estuary, the sediment transport rate and morphological seabed changes are controlled exclusively by the tidal currents and the river discharge. In this latter case, we found that the large sandbank located at the estuary mouth is responsible for the absence of wave.

Sign in / Sign up

Export Citation Format

Share Document