scholarly journals Prediction of interaction between a side overflow and bed-load transport in a channel with semi-empirical approaches

2009 ◽  
Vol 36 (11) ◽  
pp. 1755-1763 ◽  
Author(s):  
Burkhard Rosier ◽  
Jean-Louis Boillat ◽  
Anton J. Schleiss
Keyword(s):  
Engineering Practice ◽  
Bed Load ◽  
Flume Experiments ◽  
Load Transport ◽  
Bed Load Transport ◽  
Input Variables ◽  
Side Weirs ◽  
Semi Empirical ◽  
Protection Engineering

Side weirs are free overflow regulation and diversion structures commonly encountered in flood protection engineering. The lateral loss of water reduces the bed-load transport capacity in the main channel, leading to local sediment deposition near the side overflow. As a consequence, the design overflow is increased in an uncontrolled way. Since this flow–sediment interaction in such a channel has not been studied so far, systematic flume experiments have been performed. Based on these experiments, a two-dimensional empirical model to describe the longitudinal evolution of the aggraded channel reach near the weir has been developed. In addition, a simple and straightforward approach for direct estimation of the side overflow in presence of bed-load transport has been established. To be generally applicable in engineering practice, all input variables are expressed in terms of dimensionless parameters. Finally, the application of the models is demonstrated in a case study on the Rhone River in Switzerland.

Bed-Load Transport Flume Experiments on Steep Slopes

2008 ◽  
Vol 134 (9) ◽  
pp. 1302-1310 ◽  
Author(s):  
A. Recking ◽  
P. Frey ◽  
A. Paquier ◽  
P. Belleudy ◽  
J. Y. Champagne
Keyword(s):  
Bed Load ◽  
Flume Experiments ◽  
Load Transport ◽  
Bed Load Transport ◽  
Steep Slopes

scholarly journals A Shear Reynolds Number Based Investigation Method of the Bed Load Transport in Large Rivers with Complex Morphodynamics

2018 ◽  
Author(s):  
Gergely T. Török ◽  
János Józsa ◽  
Sándor Baranya
Keyword(s):  
Reynolds Number ◽  
Sediment Transport ◽  
Measurement Data ◽  
Large Rivers ◽  
Engineering Practice ◽  
Bed Load ◽  
Load Transport ◽  
Bed Load Transport ◽  
Novel Method ◽  
Bed Material

The aim of this study is to introduce a novel method which can separate sand or gravel dominated bed load transport in rivers with mixed-size bed material. In engineering practice, the Shields-Parker diagram could be used for such purposes, however, the method has certain applicability limits, due to the fact that it is based on uniform bed material and provides information rather on river-scale, instead of reach or local scale. When dealing with large rivers with complex hydrodynamics and morphodynamics the bed load transport modes can also indicate strong variation even locally, which requires a more suitable approach to estimate the locally unique behavior of the sediment transport. Here, we suggest that the decision criteria utilizes the shear Reynolds number (Re*). The method was verified against field and laboratory measurement data, both performed at non-uniform bed material compositions. The comparative assessment of the results show that the shear Reynolds number based method operates more reliably than the Shields-Parker diagram and it is expected to predict the sand or gravel transport domination with a < 5% uncertainty. The introduced results can greatly contribute to the improvement of numerical sediment transport modeling as well as to the field implementation of bed load transport measurements.

scholarly journals Bed-load transport modelling by coupling an empirical routing scheme and a hydrological-1-D-hydrodynamic model – case study application for a large alpine valley

2012 ◽  
Vol 32 ◽  
pp. 23-30 ◽  
Author(s):  
B. Gems ◽  
S. Achleitner ◽  
M. Plörer ◽  
F. Schöberl ◽  
M. Huttenlau ◽  
...  
Keyword(s):  
Transport Processes ◽  
Bed Load ◽  
Flood Events ◽  
Transport Modelling ◽  
Model Case ◽  
Alpine Valley ◽  
Routing Scheme ◽  
Load Transport ◽  
Bed Load Transport

Abstract. Sediment transport in mountain rivers and torrents is a substantial process within the assessment of flood related hazard potential and vulnerability in alpine catchments. Focusing on fluvial transport processes, river bed erosion and deposition considerably affects the extent of inundation. The present work deals with scenario-specific bed-load transport modelling in a large alpine valley in the Austrian Alps. A routing scheme founding on empirical equations for the calculation of transport capacities, incipient motion conditions and drag forces is set up and applied to the case study area for two historic flood events. The required hydraulic data result from a distributed hydrological-1-D-hydraulic model. Hydraulics and bed-load transport are simulated sequentially providing a technically well-founded and feasible methodology for the estimation of bed-load transport rates during flood events.

scholarly journals Grain shape effects in bed load sediment transport

2021 ◽  
Author(s):  
Eric Deal ◽  
Jeremy Venditti ◽  
Santiago Benavides ◽  
Ryan Bradley ◽  
Qiong Zhang ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Grain Shape ◽  
Sediment Flux ◽  
Bed Load ◽  
Flume Experiments ◽  
Natural Sediment ◽  
Shape Effects ◽  
Load Transport ◽  
Bed Load Transport ◽  
Load Sediment

Bed load sediment transport, in which wind or water flowing over a bed of sediment causes grains to roll or hop along the bed, is a critically important mechanism in contexts ranging from river restoration to planetary exploration. Despite its widespread occurrence, predictions of bed load sediment flux are notoriously imprecise. Many studies have focused on grain size variability as a source of uncertainty, but few have investigated the role of grain shape, even though shape has long been suspected to influence transport rates. Here we show that grain shape can modify bed load transport rates by an amount comparable to the scatter in many sediment transport data sets. We develop a theory that accounts for grain shape effects on fluid drag and granular friction and predicts that the onset and efficiency of bed load transport depend on the mean drag coefficient and bulk friction coefficient of the transported grains. Laboratory flume experiments using a variety of grain shapes confirm these predictions. We propose a shape-independent sediment transport law that collapses our experimental measurements onto a single trend, allowing for more accurate predictions of sediment transport and helping reconcile theory developed for spherical particle transport with the behavior of natural sediment grains.

NUMERICAL MODEL TO SIMULATE THE EROSION ON THE SLOPE DUE TO OVERTOPPING

2010 ◽  
Vol 13 (3) ◽  
pp. 78-87
Author(s):  
Hoai Cong Huynh
Keyword(s):  
Numerical Model ◽  
Flow Model ◽  
Bed Load ◽  
Experiment Data ◽  
Step Method ◽  
Morphological Model ◽  
Load Transport ◽  
Bed Load Transport ◽  
The Finite Difference Method ◽  
Good Agreement

The numerical model is developed consisting of a 1D flow model and the morphological model to simulate the erosion due to the water overtopping. The step method is applied to solve the water surface on the slope and the finite difference method of the modified Lax Scheme is applied for bed change equation. The Meyer-Peter and Muller formulae is used to determine the bed load transport rate. The model is calibrated and verified based on the data in experiment. It is found that the computed results and experiment data are good agreement.

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