scholarly journals STUDY OF FLOW BIFURCATION AT TIC 30° OPEN CHANNEL JUNCTION WHEN THE WIDTH RATIO OF BRANCH CHANNEL TO MAIN CHANNEL IS LARGE

2002 ◽  
Vol 46 ◽  
pp. 583-588 ◽  
Author(s):  
Sunil Kumar LAMA ◽  
Mikio KUROKI ◽  
Kazuyoshi HASEGAWA
Keyword(s):  
Open Channel ◽  
Main Channel ◽  
Width Ratio ◽  
Flow Bifurcation

Flow patterns in an open channel confluence with a small ratio of main channel to tributary discharge

2014 ◽  
pp. 989-996 ◽  
Author(s):  
L Schindfessel ◽  
S Creëlle ◽  
T Boelens ◽  
T De Mulder
Keyword(s):  
Open Channel ◽  
Flow Patterns ◽  
Main Channel ◽  
Small Ratio ◽  
Channel Confluence

Hydraulics of steeppass fishways

1991 ◽  
Vol 18 (6) ◽  
pp. 1024-1032 ◽  
Author(s):  
N. Rajaratnam ◽  
C. Katopodis
Keyword(s):  
Experimental Study ◽  
Velocity Profile ◽  
Channel Flow ◽  
Flow Rate ◽  
Open Channel ◽  
Maximum Velocity ◽  
Open Channel Flow ◽  
Width Ratio ◽  
Hydraulic Design ◽  
Theoretical Considerations

This paper presents the results of an experimental study on the hydraulics of steeppass fishways. Using theoretical considerations and experimental observations, an expression has been developed that relates the flow rate, slope of the fishway, and depth of flow. It was also found that the characteristic (similarity) velocity profile found earlier, for smaller values of depth to width ratio,y0/b, with the maximum velocity near the bottom, changes to a rather symmetrical profile with the maximum velocity occurring somewhere near the mid-depth for larger values of y0/b. A correlation has also been found for the maximum velocity. This paper also includes some observations on the M-type backwater curves that would appear in the fishway when the tailwater depths exceed uniform flow depths. Key words: fishways, hydraulics, turbulent flow, open-channel flow, hydraulic design.

scholarly journals A Computational Study of Interaction of Main Channel and Floodplain: Open Channel Flows

2020 ◽  
Vol 08 (11) ◽  
pp. 2526-2539
Author(s):  
Prateek Kumar Singh ◽  
Xiaonan Tang ◽  
Hamidreza Rahimi
Keyword(s):  
Open Channel ◽  
Computational Study ◽  
Main Channel ◽  
Channel Flows ◽  
Open Channel Flows

scholarly journals Tributary Channel Width Effect on the Flow Behavior in Trapezoidal and Rectangular Channel Confluences

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1344
Author(s):  
Aliasghar Azma ◽  
Yongxiang Zhang
Keyword(s):  
Recirculation Zone ◽  
Flow Behavior ◽  
Rectangular Channel ◽  
Maximum Velocity ◽  
Main Channel ◽  
Channel Width ◽  
Width Ratio ◽  
Geometrical Shape ◽  
Eddy Simulation ◽  
Flow Parameters

Channel confluences happen commonly in water transport networks and natural rivers. Utilizing a 3D CFD code, a series of numerical simulations were performed using a large eddy simulation turbulence model to investigate the effect of the variations in tributary channel width and the transverse geometrical shape of the main channel on the flow parameters and vertical structure in a T-shape confluence. The code was calibrated using the experimental data from the literature. Flow parameters were considered in ratios of tributary width to the main channel width in trapezoidal and rectangular channels. Results indicate that decreasing the width ratio of the tributary channel to the main channel significantly affects the flow structure in the confluence. Generally, it increases the width and length of the main recirculation zone. It also increases the maximum velocity near the bed, especially in cases with a trapezoidal shape. Besides, it highly affects the structure and formation of the recirculation zone in trapezoidal channels.

A Runge-Kutta Approach for the Analysis of Spatially Varied Flow

1994 ◽  
Vol 22 (4) ◽  
pp. 279-282
Author(s):  
P. W. France
Keyword(s):  
Open Channel ◽  
Numerical Technique ◽  
Surface Profile ◽  
Main Channel ◽  
Trial And Error ◽  
Side Weir ◽  
Step Procedure ◽  
Simple Alternative ◽  
Difference Form ◽  
Runge Kutta

Steady spatially varied flow has a non-uniform discharge in an open channel resulting from the addition or diminution of water along the course of the flow. The longitudinal water surface profile is normally found by expressing the appropriate general equation in finite difference form and solving using a trial and error step-by-step procedure. In this paper a simple alternative method is presented using a Runge-Kutta fourth-order numerical technique. The method is applied to a channel side weir where the discharge in the main channel is decreasing in the direction of flow.

New Approach for Predicting Flow Bifurcation at Right-Angled Open-Channel Junction

2010 ◽  
Vol 136 (9) ◽  
pp. 662-668 ◽  
Author(s):  
G. Kesserwani ◽  
J. Vazquez ◽  
N. Rivière ◽  
Q. Liang ◽  
G. Travin ◽  
...  
Keyword(s):  
Open Channel ◽  
New Approach ◽  
Flow Bifurcation

Anilox Cell Geometries For Printable Electronics and Flexible Packaging

2021 ◽  
Author(s):  
◽  
Sakulrat Foulston
Keyword(s):  
Elastic Modulus ◽  
Open Channel ◽  
High Viscosity ◽  
Width Ratio ◽  
Printable Electronics ◽  
Filament Breakup ◽  
Flexible Packaging ◽  
Wavy Channels ◽  
Ink Transfer ◽  
Breakup Time

Flexography is a major high-volume printing process used extensively for flexible packaging. The heart of flexographic press is the anilox roll, which meters the flow of ink to the image carrier (plate) by virtue of the engraved cells on the surface. The anilox was original engraved mechanically using a stylus to peck at the surface. This limited the size and profile of the engraved cells. However, laser engraving has enabled much more control with a variety of shapes and aspect ratios. Much has been claimed by the manufacturers for these new designs – improved ink transfer, higher volumes of ink transfer and better half tone reproduction – on the basis of industrial field trials. The objective of the research reported in this thesis has been to quantify the ink release from the anilox to the plate for both traditional cell profiles and the open channel designs.Previously, the ink release was mostly determined by examining the optical density of the print products. The optical density is a qualitative indicator of the ink release from anilox cells. These studies were limited to closed anilox cells with a low ink viscosity, as typically used for graphic prints. This study explores an extended range of anilox cell shapes, including open channel geometries, and the ink viscosities. The ink released from the anilox cells has been be directly measuring and quantified.Experiments were performed printing directly to glass and on flexible packaging at a commercial printers to establish the current industry position. A laboratory scale printability tester was then used to study ink release using three inks: UV Cyan, Carbon and Silver. These represented a link to the graphic experiments in previous published studies, while the Carbon and Silver were highly viscoelastic functional inks used in printed electronics. Four cell geometries were used: laser engraved closed cells, extended hexagonal and wavy channels together with mechanically engraved conventional closed pyramid cells. The laser engraved anilox afforded the opportunity to vary key parameters of cell width, depth, profile and volume. A brief exploration of print speed was also undertaken with exemplar anilox of each cell type. The main study considered ink transfer to a 100% solid plate, as this would allow the ink release to be studied without influence of the plate distorting into the cells thereby extracting more ink. A limited study was then undertaken with a half tone plate to establish the impacted on ink transfer.The amount of ink transferred was highly dependent on the absolute volume of cells, i.e. the amount of ink available on the anilox. The anilox cells with wider, shallower and smaller depth-to-width ratio released a higher proportion of the ink. The ink’s physical characteristics of viscoelasticity and extensional viscosity also determine the proportion of ink transferred.The anilox hexagonal closed cells (typically used in the flexographic printing process) performed best with the low viscosity ink. The information gaining from this study would aid in the design of anilox cell geometries and development of ink characteristics to enhance its capability for functional print applications such as printable electronics. The anilox wavy channels released the greatest proportion of the ink with high viscosity, elastic modulus, and filament breakup time. The anilox wavy channel has the potential to be used for the functional print as it increased the release of paste-like ink. Additionally, it improved the ink lay-down. The anilox engraving technique affected the ink release. The anilox cells, which were engraved by the laser technique, gave greater ink release comparing to the anilox cells, which were engraved by the mechanically engraving technique. The increase of the dot coverage increased the ink release out of the anilox cells because of the increase of the receiving area. However, the increase of the ink release plateaued after the dot coverage of 50% for UV Silver because of its large filament breakup time.The characteristics of ink influenced the ink release out of the anilox cells. Unlike previous work which examined only the ink viscosity, this studied included ink elastic modulus and filament breakup. The ink with high viscosity and elastic modulus, but small filament breakup time gave greatest ink release for all anilox shapes.When the printing speed increased, it decreased the ink release due to two factors; reduction of engagement time between the anilox cells and the plate (reducing time for ink to transfer) and enlargement of the filament extension rate (reducing the amount of ink transfer). The decrease of ink release was affected by the ink characteristics and the anilox cells shapes. The decrease of ink release was significant when UV Cyan ink (small viscosity and elastic modulus) was used with the anilox open cells and wavy channels. Contrarily, the decrease of ink release was insignificant when UV Carbon and Silver inks (large viscosity and elastic modulus) was used with the anilox open cells and wavy channels.The experimental data was analysed and the critical parameters in releasing the ink of the anilox cells were identified. The depth of anilox cell was the most critical parameter; the shallower cell depth released a higher proportion of the ink. The ratio of depth-to-width was the second most important parameter in determining the ink release. The smaller depth-to-width ratio released more ink. The width of anilox cell could not be used as a parameter predicting the ink release because the wider anilox cell did not always release the higher proportion of the ink.

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