Effects of vegetation patch density on flow velocity characteristics in an open channel

Open and closed channel flow flows are distinct, the flow in the channels will constantly change. The flow will also be altered if the water level or flow velocity changes. It was found that employing the Pitot Tube Portable yielded findings identical to those calculated by other methods. A water transfer system is made up of natural or artificial structures via which water is moved from one site to another. The carrier building may be open or closed, depending on whether you want to utilize it as a shipping or receiving location. An open channel with a relatively narrow opening at the top is known as an open conduit. The speed data collection technique is carried out vertically, with a review point as illustrated above. The velocity of the flow was measured using a Pitot Tube Portable Automatic tool. The results are entered into the Froude number (fr) after each review point to determine the type of velocity flow at each Review point. The normal flow velocity distribution pattern emerges at the measurement sites of 450 cm, 500 cm, and 550 cm.

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Studi Kecepatan Aliran Air dengan Menggunakan Tabung Pitot

INTEK Jurnal Penelitian ◽

10.31963/intek.v5i1.194 ◽

2018 ◽

Vol 5 (1) ◽

pp. 14

Author(s):

Muhammad Taufik Iqbal ◽

Zulvyah Faisal

Keyword(s):

Flow Velocity ◽

Water Flow ◽

Flow Rate ◽

Open Channel ◽

Flow Analysis ◽

Distribution Channel ◽

Research Process ◽

Flow Speed ◽

Water Flow Velocity ◽

Speed Distribution

The tools and methods used in the measurement of water flow velocity are now very diverse, such as by using Venturi Meter, Orifice, Current Meter, Pitot Tube, and so forth. To learn more about water flow velocity measurement method, in order to improve professionalism in the field of water resources can be done research at Hydraulics Laboratory by researching Water Flow Analysis by Using Pitot Tubes. The research process will be carried out using three varied channel basis samples: reviewing the velocity of the water flow at the bottom of the channel with slippery base, reviewing the flow rate of the water on the gravel base channel, and reviewing the flow rate of the water on the channel with the decking concrete base. The expected result of this research is knowing the distribution of velocity in a cross section such as drainage channel, irrigation channel and river, so construction of water structure can be adjusted position placement in the open channel section. In addition it can be used as a reference in planning an open channel. One of the benefits to construction cofferdam construction speed distribution is to determine the dewatering system to be carried out during construction.Keywords— Flow Speed, Speed Distribution. Channel Basic Variations

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Effect of a Lateral Jet on the Turbulent Flow Characteristics of an Open Channel Flow with Rigid Vegetation

Water ◽

10.3390/w10091204 ◽

2018 ◽

Vol 10 (9) ◽

pp. 1204 ◽

Cited By ~ 2

Author(s):

Sufen Teng ◽

Minquan Feng ◽

Kailin Chen ◽

Weijie Wang ◽

Bangmin Zheng

Keyword(s):

Flow Velocity ◽

Reynolds Stress ◽

Water Flow ◽

Channel Flow ◽

Turbulence Intensity ◽

Open Channel ◽

Aquatic Vegetation ◽

Open Channel Flow ◽

Rigid Vegetation ◽

Bodies Of Water

Aquatic vegetation can purify polluted bodies of water and beautify the environment, as well as alter the structure of water flow and affect the migration and diffusion of pollutants in bodies of water. Vegetation can significantly change the original water flow, especially in cases in which aquatic vegetation interacts with a jet. Characteristics of jet flow open channels without vegetation have been studied, but research on the characteristics of open-channel flows under the action of lateral jets and in the presence of vegetation are rare. High-frequency particle image velocimetry (PIV) was used to measure a lateral jet in water with rigid vegetation and our results were compared to the lateral jet flow field in water without vegetation. The results show that the vegetation arrangement and vegetation resistance cause significant changes. The presence of vegetation increased the surface velocity of the water, and the flow velocity decreased in the interior area of the vegetation and near the bottom of the water tank. The changes in flow velocity with changes in water depth displayed “S” type and anti-“S” type distributions, and the flow velocity of free layer was approximately logarithmic. Due to vegetation resistance and jet pressure differences, the lateral jet trajectory in water with vegetation was more likely to bend than in water without vegetation. The turbulence intensity and Reynolds stress had different distributions for water with and without vegetation. At the top of the vegetation and near the water surface, turbulent mixing of the water flow was strong, the flow velocity gradient was large and the turbulence intensity and the Reynolds stress reached their maxima. The effects of a lateral jet on an open-channel flow were compared for different vegetation conditions, revealing that a rhombic vegetation arrangement has a stronger deceleration effect than other arrangements. The theoretical results can be applied to wastewater discharge into vegetation channels.

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Effects of flow velocity and depth on the rates of reaeration and bod removal in a shallow open channel

Water Science & Technology ◽

10.2166/wst.1997.0297 ◽

1997 ◽

Vol 35 (8) ◽

pp. 57-67

Author(s):

Horng-Guang Leu ◽

C. F. Ouyang ◽

Tze-Yi Pai

Keyword(s):

Analytical Solution ◽

Flow Velocity ◽

Open Channel ◽

Rate Coefficient ◽

Removal Rate ◽

Sedimentation Coefficient ◽

Inverse Correlation ◽

Flow Conditions ◽

Batch Tests ◽

Bod Removal

This study developed an analytical solution of reaeration rate coefficient (K2) and modified the equation of BOD removal in a shallow artificial open channel. A series of well-controlled batch tests were carried out to measure the K2 and BOD removal rate in the channel at different flow conditions. The results of these tests indicated that measured K2 within the developing zone of the laminar boundary layer is better described by the analytical solution of this study than by the five semi-empirical formulae mentioned in this paper. On the other hand, a resuspension-sedimentation coefficient, Rs, was added to the BOD removal equation to describe the variation in BOD due to varied flow conditions. Based on the results of the experimental data the following conclusions in the BOD removal process were reached. It was found that a direct correlation exists between the flow velocity to depth ratio (U/h) and the deoxygenation rate coefficient (K1), but there is an inverse correlation between U/h and Rs as well. This modified BOD removal equation can predict BOD removal rate at different travel times or known downstream distances in an open channel under varied flow conditions.

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OPEN CHANNEL FLOW VELOCITY PROFILES FOR DIFFERENT REYNOLDS NUMBERS AND ROUGHNESS CONDITIONS

International Journal of Research in Engineering and Technology ◽

10.15623/ijret.2014.0301069 ◽

2014 ◽

Vol 03 (01) ◽

pp. 400-405 ◽

Cited By ~ 1

Author(s):

Md Abdullah Al Faruque .

Keyword(s):

Flow Velocity ◽

Channel Flow ◽

Open Channel ◽

Open Channel Flow ◽

Reynolds Numbers ◽

Velocity Profiles

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Turbulent hydrodynamics through cross-sections at upstream, interior and downstream of sparse vegetation patch in open channel flow

River Sedimentation ◽

10.1201/9781315623207-70 ◽

2016 ◽

pp. 360-367

Author(s):

Debasish Pal ◽

Soumen Maji ◽

Prashanth Reddy Hanmaiahgari ◽

Minh Duc Bui ◽

Peter Rutschmann

Keyword(s):

Channel Flow ◽

Cross Sections ◽

Open Channel ◽

Open Channel Flow ◽

Vegetation Patch ◽

Sparse Vegetation

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An open channel with an emergent vegetation patch: Predicting the longitudinal profiles of velocities based on exponential decay

Journal of Hydrology ◽

10.1016/j.jhydrol.2019.124429 ◽

2020 ◽

Vol 582 ◽

pp. 124429 ◽

Cited By ~ 2

Author(s):

Chao Liu ◽

Yuqi Shan ◽

Wei Sun ◽

Chunhao Yan ◽

Kejun Yang

Keyword(s):

Exponential Decay ◽

Open Channel ◽

Emergent Vegetation ◽

Vegetation Patch ◽

Longitudinal Profiles

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Experiment and Computation of Morphological Response to a Vegetation Patch in Open-Channel Flows with Erodible Banks

Water ◽

10.3390/w11112255 ◽

2019 ◽

Vol 11 (11) ◽

pp. 2255 ◽

Cited By ~ 1

Author(s):

Hyung Suk Kim ◽

Ichiro Kimura ◽

Yasuyuki Shimizu

Keyword(s):

Morphological Changes ◽

Bank Erosion ◽

Small Scale ◽

Morphological Response ◽

Erosion And Deposition ◽

Vegetation Patch ◽

Future Design ◽

Channel Slope ◽

Patch Density ◽

Averaged Model

This study describes morphological changes with a vegetation patch using both laboratory experiments and numerical simulations. Four experimental cases are carried out with two patch densities and without a patch. The patch is constructed with emergent cylinders of 5 mm in a staggered array and it is located at the mid-channel. A 2D depth-averaged model is proposed to simulate flow and morphological change with vegetation. For non-vegetation cases, channel widening occurs with bank erosion, whereas the added patch in open channels causes significant bank erosion opposite and downstream of the patch, and failed sediment is deposited downstream of the patch. Local scour is observed near the lateral edge of the patch, and its depth increases with increasing patch density. Small-scale scour occurs in the immediate vicinity of cylinders within the patch due to increased turbulence. Averaged channel width increases with increasing discharge, channel slope and the patch density. Comparisons with experimental data show the numerical model predicts spatial patterns of erosion and deposition as well as lateral bank erosion caused by the vegetation patch reasonably well, so could be a useful tool for the future design and assessment of river restoration works involving vegetation.

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