Prediction of bedload transport rate using a block combined network structure

2021 ◽  
Author(s):  
Seyed Abbas Hosseini ◽  
Abbas Abbaszadeh Shahri ◽  
Reza Asheghi
Keyword(s):  
Network Structure ◽  
Bedload Transport ◽  
Transport Rate

scholarly journals Variability of bedload transport rate during flood flows in the Zagożdżonka River

2010 ◽  
Vol 42 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Zbigniew Popek
Keyword(s):  
Laboratory Experiments ◽  
Bedload Transport ◽  
Transport Rate ◽  
Environmental Restoration ◽  
Bed Shear Stress ◽  
Measurement Results ◽  
Gauge Station ◽  
Flood Flows ◽  
Bedload Sediment ◽  
Flood Flow

Variability of bedload transport rate during flood flows in the Zagożdżonka River The paper presents the measurement results of bedload sediment transport during the flood flows observed in the Zagożdżonka River. The point for measuring the bedload transport, equipped with sediment catcher, devices for continuous measurements, and automated data recording, was localized above the Czarna gauge station in catchment studied by the Department of Hydraulic Engineering and Environmental Restoration, Warsaw University of Life Sciences - SGGW. The results of bedload transport measurements during one of the flood flow waves were compared to those calculated by using the Bagnold's formula. To determine the critical bed-shear stress, the Author's formula resulting from laboratory experiments, was used. Calculated variability of bedload transport rate during analyzed flood flow wave apparently differed from that directly measured. Nevertheless, mass of bedload achieved from calculations was lower by 6% than that from measurements, which can be considered as good result consistence.

Two Stochastic Fraction Bedload Transport Rate Models for Nonuniform Sediment

2013 ◽  
Vol 295-298 ◽  
pp. 1894-1897
Author(s):  
Bin Zhang ◽  
Xing Nian Liu ◽  
Feng Guang Yang
Keyword(s):  
Size Fraction ◽  
Bedload Transport ◽  
Transport Rate ◽  
Incipient Motion ◽  
Transport Models ◽  
Probabilistic Distribution ◽  
Sediment Transportation ◽  
Nonuniform Sediment ◽  
Laboratory Flume ◽  
Natural Data

Based on a method stochastic processes, two new bedload transport models for the ith size fraction nonuniform sediment are theoretically developed by using a stochastic model of sediment exchange and the probabilistic distribution of fractional bedload transport rates. The relations, proposed recently by Yang, for the probability of fractional incipient motion and for the average velocity of particle motion are introduced to bedload formulas. Plenty of experimental data for the bedload transport rate of uniform sediment are used to determine parameters. Finally, the two models are verified with natural data expressing the transport of nonuniform sediment under full motion in laboratory flume. The result shows that the experimental observations agree well with the predicted fractional bedload transport rates. Comparison of the theory with field data shows that the proposed formula still applies to uniform sediment transportation condition as long as the relevant parameters for uniform sediment are taken into account.

scholarly journals Temporal variations of bed load transport rate and the grain size distribution of non-uniform size sediment during a constant flow rates

2018 ◽  
Vol 195 ◽  
pp. 05001
Author(s):  
Yusron Saadi ◽  
Ida Bagus Giri Putra ◽  
Agus Suroso
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Sampling Period ◽  
Degradation Process ◽  
Temporal Variations ◽  
Bedload Transport ◽  
Transport Rate ◽  
Uniform Size ◽  
Short Period

Bedload transport rates at a point using both laboratory and field measurement vary with time, from almost zero to several folds of the mean rate. The need to carry out point measurements over a sufficiently long sampling period is very important to cover inconsistency in the transport rate during a short period of observation. In this experiment the bedload was collected at a slot type sediment trap with ten-minute intervals throughout the tests. The aim was to examine the behaviour of mixed grain size sediment transportation during constant flowrates. Two hydrographs were applied to quantify the transport mode changes caused by an increase in time length as the mixtures were continuously exposed to the flow. It shows that intense bed degradation process occurred within three hours of the tests as indicated by almost identical rates of bedload transport during this period and the diminishing rate in the remaining hours. This reflects that a stable bed was achieved after three hours in which the armouring process was believed to take place. The grain size distribution suggests that the proportion of fine mode was relatively stable and the modal grain size of this mode experienced a similar pattern throughout the tests whilst the coarse mode was inconsistent and varied periodically.

Bedload transport rate prediction: Application of novel hybrid data mining techniques

2020 ◽  
Vol 585 ◽  
pp. 124774 ◽  
Author(s):  
Khabat Khosravi ◽  
James R. Cooper ◽  
Prasad Daggupati ◽  
Binh Thai Pham ◽  
Dieu Tien Bui
Keyword(s):  
Data Mining ◽  
Bedload Transport ◽  
Transport Rate ◽  
Data Mining Techniques ◽  
Rate Prediction ◽  
Hybrid Data

Large eddy simulation of bed formation in subaqueous bedload

2020 ◽  
Author(s):  
Chenwei Zhao
Keyword(s):  
Large Eddy Simulation ◽  
Bedload Transport ◽  
Main Flow ◽  
Transport Rate ◽  
Surface Elevation ◽  
Computational Time ◽  
Low Speed ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Low Speed Streaks

<p>Large eddy simulation of incompressible turbulent flow over a loose bed of spherical particles are investigated in an open channel. Eulerian and Lagrangian point-particle methods is applied to solve the Navier-Stokes equations and particle motion respectively and the particle-flow interaction is also considered. A new method solving particle-particle collisions is utilized for the first time to reduce the computational time spending on calculating the pairwise distances between particles. A turbulent fluid condition from the experiment of Robert and Uhlman (2001) are chosen of which the corresponding sediment patterns are ‘ripple’. Flow over the formed bed is considered and it is found that double-averaged Reynolds stresses including shear stress and three normal stresses reach their peak values near the bed. However, affected by the movable bed, they decay quickly as the height increases. The flow direction slightly rises over the stoss-side of ripples and falls after the crest and the velocity magnitude of time-averaged flow accelerate and decelerate before and after the crest of ripples as well. Hence, recirculation zones and clockwise vorticity appear at the trough of the bed where kolk boil vortices like hairpins and elongated streamwise vortices is also evident. Coherent structures, in the form of high- and low-speed streaks near the bed are also affected by the bed formation. The near-bed low-speed streaks entrain into the main flow domain over the stoss-side of ripples and the high-speed fluid streaks from the main flow rush toward the bed over the leeside of ripples. The bedload transport rate is well represented by previous empirical formulas. The bed surface elevation changes from upstream to downstream with time and there is a difference in the direction of sediment transport which is obvious three-dimensionality. In addition, it is also found that the bed surface elevation shows a positive correlation with particle streamwise velocity and entrainment rate which means higher bed elevation leads to larger bedload transport rate.</p>

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