scholarly journals Study on Flow Velocity Distribution in Open Channel With Flexible Vegetation

2021 ◽  
Vol 12 ◽  
Author(s):  
Shiyu Wang ◽  
Yi Zhou ◽  
Tongshu Li ◽  
Song Li ◽  
Mingwu Zhang ◽  
...  
Keyword(s):  
Velocity Distribution ◽  
Flow Velocity ◽  
Flow Measurement ◽  
Open Channel ◽  
Maximum Flow ◽  
Distribution Model ◽  
Turbulence Structure ◽  
River Channels ◽  
Microscopic Mechanism ◽  
Flexible Vegetation

Ecological management of river channels is a hot topic for current sustainable development and flow measurement of ecological river is an important part. In this article, a flow velocity distribution model of the channel containing flexible vegetation is constructed from the vegetation riverbed theory and the bursting phenomenon to reveal the microscopic mechanism of the flow velocity distribution in the upper layer of vegetation. In the vegetation riverbed law, the effect of flexible vegetation is evaluated by the mixed length formula. The bursting phenomenon law considers the influence of the channel sidewalls on the flow and a two-dimensional velocity model is established by introducing the concept of average turbulence structure. The mechanism of the downward shift of the maximum flow velocity point on the channel sidewall is explained. The verification of the calculated velocity profiles is carried out based on data obtained in laboratory experiments. The results show that the combination of the two models can well describe the velocity distribution of the whole channel. At the end, the phenomenon of flow velocity zoning in open channel is discussed, which provides a solution for flow measurement in ecological channel.

scholarly journals Submerged flexible vegetation impact on open channel flow velocity distribution: An analytical modelling study on drag and friction

2019 ◽  
Vol 12 (2) ◽  
pp. 121-128 ◽  
Author(s):  
Jaan H. Pu ◽  
Awesar Hussain ◽  
Ya-kun Guo ◽  
Nikolaos Vardakastanis ◽  
Prashanth R. Hanmaiahgari ◽  
...  
Keyword(s):  
Velocity Distribution ◽  
Flow Velocity ◽  
Channel Flow ◽  
Open Channel ◽  
Open Channel Flow ◽  
Analytical Modelling ◽  
Flexible Vegetation ◽  
Vegetation Impact ◽  
Modelling Study

scholarly journals Experimental Study on the Effect of Triangular Plate Barrier Height on Flow Velocity Distribution in Open Channels

2021 ◽  
Vol 2 (2) ◽  
pp. 31-36
Author(s):  
Lhiung Phung Hwa
Keyword(s):  
Velocity Distribution ◽  
Flow Velocity ◽  
Open Channel ◽  
Pitot Tube ◽  
Closed Channel ◽  
Velocity Flow ◽  
Velocity Changes ◽  
Automatic Tool ◽  
Data Collection Technique ◽  
Narrow Opening

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.

Investigation on Velocity Distribution in the Subchannels of Pin Bundle With Wrapping Wire: Evaluation of Reynolds Number Dependence in 3-Pin Bundle

2020 ◽  
Author(s):  
Kosuke Aizawa ◽  
Tomoyuki Hiyama ◽  
Masahiro Nishimura ◽  
Akikazu Kurihara ◽  
Katsuji Ishida
Keyword(s):  
Velocity Distribution ◽  
Flow Velocity ◽  
Fast Reactor ◽  
Light Transmission ◽  
Transmission Rate ◽  
Heat Removal ◽  
Maximum Flow ◽  
Water Model ◽  
Local Flow ◽  
Maximum Flow Velocity

Abstract A sodium-cooled fast reactor is designed to attain a high burn-up core in commercialized fast reactor cycle systems. In high burn-up fuel subassemblies, the deformation of fuel pin due to the swelling and thermal bowing may decrease local flow velocity in the subassembly and influence the heat removal capability. Therefore, it is important to obtain the flow velocity distribution in a wire wrapped pin bundle. In this study, the detailed flow velocity distribution in the subchannel has been obtained by PIV (Particle Image Velocimetry) measurement using a wire-wrapped 3-pin bundle water model. The test section consisted of an irregular hexagonal acrylic duct tube and fluorinated resin pins which had nearly the same refractive index with that of water and a high light transmission rate. This enables to visualize the inner subchannel through the outer pins. Flow velocity conditions in the pin bundle were set from 0.036 m/s (Re = 270) to 1.6m/s (Re = 13,500). From the PIV results, it was confirmed that the normalized flow velocity near the wrapping wire in low Re number condition was decreased relatively compared to that in high Re number condition. In the region away from the wrapping wire, the maximum flow velocity was increased by decreasing the Re number. In particular, the maximum flow velocity was more than twice the cross section average velocity in the laminar flow (Re = 270). Moreover, the PIV measurements by using the 3-pin bundle geometry without the wrapping wire were conducted. From the results, the effect of the wrapping wire on the flow field in the subchannel was understood. There experimental results useful not only for understanding of pin bundle thermal hydraulics but also code validation.

scholarly journals Experimental Study on the Influence Factors of Flow Velocity Structure and Turbulent Characteristics in Open Channel with Biomimetic Grass

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Changjing Fu ◽  
Jinguo Wang ◽  
Tianlong Zhao ◽  
Yi Lv
Keyword(s):  
Velocity Field ◽  
Velocity Distribution ◽  
Flow Velocity ◽  
Open Channel ◽  
Velocity Structure ◽  
Influence Factors ◽  
Vertical Plane ◽  
Velocity Variation ◽  
Probability Density Distribution ◽  
Turbulent Characteristics

The problem of suspension treatment of subsea oil-gas pipelines has been highly concerned by engineering construction units and researchers. The current research indicates that the bionic sea grass can effectively reduce the flow rate, promote sediment deposition, and control the development of the pipeline suspension area. The velocity distribution of open channel flow with bionic grass is very complex. The height and laying space of bionic grass will affect the flow velocity distribution. At present, the flow velocity in open channels with bionic grass is mainly studied by measuring the velocity variation at the front, middle, and back of bionic grass. Few effective measurements are made for the full velocity field. The velocity field distribution of bionic aquatic grass along the vertical plane is measured by using standard particle image velocimetry (PIV). The effects of height and laying space of bionic grass on probability density distribution, spatial correlation of pulsating velocity, turbulence intensity, Reynolds stress and turbulent kinetic energy in the open channel after the protection section of bionic grass are further analyzed.

scholarly journals Flow velocity behavior programming on open channel bends

2021 ◽  
Vol 878 (1) ◽  
pp. 012049
Author(s):  
S Setiyadi
Keyword(s):  
Flow Velocity ◽  
Transverse Direction ◽  
Open Channel ◽  
Transverse Velocity ◽  
River Channel ◽  
River Channels ◽  
Flood Prevention ◽  
Channel Bend ◽  
Secondary Velocity

Abstract Flow velocity on open channel bends generally experiences additional velocity which is called secondary velocity. This paper aims to analyse and calculate the velocity that occurs in an open channel bend in general. The calculation that the writer uses is the calculation with fortran programming, in a case study of a river that bends, where the variables that must be present are given. The results of calculations and measurements of Secondary Speeds that occur at channel bends in this Open Channel will be very useful for river channel improvement or flood prevention in river channels, especially on existing bends. The conclusion is that at the bend of an open channel or river, there will be an increase in flow velocity in the transverse direction. This additional velocity is caused by the additional secondary velocity, namely the transverse velocity.

scholarly journals Experimental Study on Flow Velocity Structure and Turbulence Characteristics in Open Channel with Biomimetic Grass

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Changjing Fu ◽  
Jinguo Wang ◽  
Tianlong Zhao ◽  
Yangming Xu ◽  
Yi Lv
Keyword(s):  
Velocity Field ◽  
Velocity Distribution ◽  
Flow Velocity ◽  
Open Channel ◽  
Oil And Gas ◽  
Velocity Structure ◽  
Water Channel ◽  
Vertical Plane ◽  
Velocity Variation ◽  
Probability Density Distribution

The problem of suspension treatment of oil and gas pipelines has been highly concerned by engineering construction units and researchers. Research shows that the bionic grass can effectively reduce the flow rate, promote sediment deposition, and control the development of the pipeline suspension area. The velocity distribution of open channel flow with bionic grass is very complex. The height and spacing of bionic grass will affect the flow velocity distribution. At present, the flow velocity in open channels containing bionic grass is mainly studied by measuring the velocity variation in the front, middle, and back of bionic grass, but few effective measurements are made for the full velocity field. This paper describes the use of modern means of an advanced test, using standard particle image velocimetry (PIV) measurements with bionic grass along the water channel to the vertical plane of the distribution of the velocity field. The probability density distribution, spatial correlation of pulsating velocity, turbulence intensity, Reynolds stress, and turbulent kinetic energy in the open channel after the protection section of bionic grass were further analyzed.

Research on the Flow Measurement Method and Equipment of Open Channel

2013 ◽  
Vol 303-306 ◽  
pp. 567-572
Author(s):  
Cheng Li Wang ◽  
Wei Guo Zhao ◽  
Lian Chao Dai ◽  
Wei Zhu
Keyword(s):  
Velocity Distribution ◽  
Flow Measurement ◽  
Measurement Method ◽  
Open Channel ◽  
Simulation Method ◽  
Measurement Equipment ◽  
Area Method ◽  
Fluent Simulation

In order to solve the problems of flow measurement and to obtain the sectional velocity distribution of open channel, the FLUENT simulation method was adopted. The velocity-area method based on the sectional velocity distribution was introduced, and the flow measurement equipment of open channel was also designed. The experiment result shows that the error of the method is less than 1%.

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