scholarly journals Effect of a Submerged Vane-Field on the Flow Pattern of a Movable Bed Channel with a 90° Lateral Diversion

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 828
Author(s):  
Joana Baltazar ◽  
Elsa Alves ◽  
Gökçen Bombar ◽  
António Heleno Cardoso
Keyword(s):  
Flow Pattern ◽  
Water Discharge ◽  
Main Channel ◽  
Bed Load ◽  
Bed Morphology ◽  
Discharge Ratio ◽  
Submerged Vane ◽  
Diversion Channel ◽  
Movable Bed ◽  
Lateral Diversion

This laboratory study focused on the effect of a submerged vane-field on the flow pattern and bed morphology near and inside the entrance reach of a movable bed 90° lateral diversion. The system was modelled under live bed conditions for a water discharge ratio of ≈0.2. Two experiments were run until bed equilibrium was reached: with and without a vane-field installed close to the diversion entrance to control the transfer of sediments into the diversion channel. The equilibrium bed morphology and the associated 3D flow field were measured in great detail. The bed load diverted into the diversion was reduced by approximately one quarter due to the action of the vane-field. The vanes prevented the formation of the diversion vortex in the main channel, upstream of the diversion’s entrance, thus contributing to that decrease. They also created a main channel vortex that started at the most upstream vanes and further decreased the amount of bed load entering the diversion. The flow separation zone inside the diversion was larger with vanes, but conveyance was balanced through a slightly deeper scour trench therein. The flow structures described were confirmed through the measurements of the turbulent kinetic energy.

scholarly journals The Effect of Confluence Angle on the Flow Pattern at a Rectangular Open-Channel

2014 ◽  
Vol 4 (1) ◽  
pp. 576-580
Author(s):  
F. Rooniyan
Keyword(s):  
Flow Pattern ◽  
Separation Zone ◽  
Morphological Changes ◽  
Flow Behavior ◽  
Main Channel ◽  
Flow Discharge ◽  
Urban Sewage ◽  
Discharge Ratio ◽  
Drainage Channels ◽  
Junction Geometry

Flow connection in channels is a phenomenon which frequently happens in rivers, water and drainage channels and urban sewage systems. The phenomenon appears to be more complex in rivers than in channels, especially at the y-junction bed joint that causes erosion and sedimentation at some areas resulting to morphological changes. Flow behavior at the channel junction area depends on variables such as channel geometry, discharge ratio, tributary width and y-junction connection angle of the channel, bed level changes at the bed joint, flow characteristic at the bed joint upstream and flow Froude number in different sections. In this research, fluent numerical model and junction angles of 30o, 45o & 60o are used to analyze and evaluate the effect of channel junction geometry on the flow pattern and the flow separation zone dimensions in different ratios of flow discharge (upstream channel discharge to total discharge of the flow). Results for two ratios of flow discharge are represented. Results are in agreement with earlier studies and it is shown that the change of the channel crossing angle affects the flow pattern in the main channel and also that the dimensions of the created separation zone in the main channel become larger when the crossing angle increases. This phenomenon can also be observed when the flow discharge ratio is lower. Analysis showed that the least dimension of the separation zone will be at the crossing angle of 45o .

Unsteady flow in straight alluvial streams: modification of individual dunes

1979 ◽  
Vol 91 (3) ◽  
pp. 497-512 ◽  
Author(s):  
Jørgen Fredsøe
Keyword(s):  
Unsteady Flow ◽  
Water Depth ◽  
Laboratory Experiments ◽  
Water Discharge ◽  
Sudden Change ◽  
Mean Value ◽  
Bed Load ◽  
Shear Distribution ◽  
Model Flow ◽  
Phase Differences

Changes in dune properties due to a sudden change in the water discharge are analysed. The transport of sediment is assumed to occur mainly as bed load and the square of the Froude number must be much smaller than unity. The theory is based on similarity in the bed-shear distribution close to the dune top just before and just after the change in the water discharge. The model is found to agree with laboratory experiments. Further, by use of this model, flow in a river where the water discharge oscillates weakly around a constant mean value has been treated. Hereby the variation in the phase differences between sediment transport, water depth and water discharge with the period of the oscillation is calculated. The results agree qualitatively with observations.

scholarly journals Experimental Study of Submerged Vanes in Intakes under Sediment Feeding Conditions

2018 ◽  
Vol 40 ◽  
pp. 03016
Author(s):  
Aslı Bor Türkben
Keyword(s):  
Water Intake ◽  
River Flow ◽  
Flow Direction ◽  
Main Channel ◽  
Bed Topography ◽  
Before And After ◽  
Submerged Vane ◽  
Solid Discharge ◽  
Submerged Vanes ◽  
Intake Structure

Sediment is transported along the river flow and deposited in the mouth of the intake structure over time and reducing the water intake capacity. Nowadays, many water intake structures lose their function and are closed to operation. To deal with this problem, recently, submerged vane application has offered a practical and economical solution. The aim of this study was to evaluate the efficiency of three vane installations under sediment feeding conditions by comparing the bed topography before and after vanes were installed. For that purpose, experiments were carried out in a laboratory channel running for 90-degree intake angle. Three vanes were installed in one column at near the intake entrance. The vanes dimensions were equal to; 3cm height, 12cm long, 10 mm thick, and aligned with α = 20° angle to flow direction. The tests were run until equilibrium was reached, i.e. when the outgoing solid discharge was equal or larger than 90% of the incoming. Once the bed topography remained stable, bed and water level surfaces were measured. tests were carried out by feeding sediment from upstream of the main channel.

scholarly journals Simulation of flow pattern at rectangular lateral intake with different dike and submerged vane scenarios

2017 ◽  
Vol 10 (3) ◽  
pp. 246-255 ◽  
Author(s):  
Hojat Karami ◽  
Saeed Farzin ◽  
Mohammad Tavakol Sadrabadi ◽  
Hasan Moazeni
Keyword(s):  
Flow Pattern ◽  
Submerged Vane

scholarly journals RIVERBED EVOLUTION OF YANGTZE ESTUARY AND ITS RESPONSE TO THE HYDRODYNAMIC CHANGES AT UPSTREAM

2012 ◽  
Vol 1 (33) ◽  
pp. 92
Author(s):  
Yongping Chen ◽  
Ninglin Jiang ◽  
Changkuan Zhang
Keyword(s):  
Cross Sections ◽  
Water Depth ◽  
River Discharge ◽  
Numerical Experiments ◽  
Yangtze Estuary ◽  
Main Channel ◽  
Depth Profiles ◽  
Discharge Ratio ◽  
Upper Boundary

The riverbed evolution of upper part of Yangtze estuary, Chengtong reach, is analyzed by comparison of 6 sets of bathymetry data during 1977~2011. The significant changes of water depth profiles along 6 representative cross-sections indicate the reach is still in the process of development. In order to get a better understanding of the effect of river discharge at upstream on the riverbed evolution of Chengtong reach, a series of numerical experiments are implemented by specifying different river discharge conditions at the upper boundary. The corresponding discharge ratio at main sub-reaches is compared to reveal the response of the riverbed evolution to the hydrodynamic changes at upstream. The results show that with the increase of river discharge, the discharge ratio in the main channels of Fujiangsha sub-reach and Rugaosha sub-reach increases, but it changes to decrease when the upstream river discharge becomes very large; however, the discharge ratio in the main channel of Tongzhousha sub-reach always decreases with the increase of river discharge at upstream.

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