scholarly journals OPEN CHANNEL TURBULENCE CHARACTERISTICS IN A ROUGHNESS LAYER FOR SMALL WATER DEPTH RELATIVE TO ROUGHNESS ELEMENTS HEIGHT

2016 ◽  
Vol 72 (4) ◽  
pp. I_511-I_516 ◽  
Author(s):  
Saqib HABIB ◽  
Norio TANAKA ◽  
Yuta YOSHIZAWA
Keyword(s):  
Water Depth ◽  
Open Channel ◽  
Turbulence Characteristics ◽  
Small Water ◽  
Roughness Elements

A Study of the Average Flow in Open Channel with Baffle Blocks Distributed Uniformly

10.29007/zx1w ◽  
2018 ◽  
Author(s):  
Dung Tien Tran ◽  
Anh Tuan Le ◽  
Hong Nhung Le ◽  
Viet Hung Ho
Keyword(s):  
Water Level ◽  
Water Depth ◽  
Open Channel ◽  
Block Size ◽  
Average Flow ◽  
Modelling Studies ◽  
Baffle Block

A study of average flow in open channel with baffle blocks distributed uniformly has been considered by using channel with varied slopes. In this article, experimental and modelling studies were introduced when the correlation between the water depth and baffle block size is significant. The objective of the work is to give the rudimentary relations between discharge and water level in the channels. When the water depth is large, the effect of bottom channel friction on the flow is relatively small. This paper also gives applications of the software ‘Telemac-2D’ to simulate the flow under different conditions.

scholarly journals Turbulence characteristics of open channel flow over non-equilibrium 3-D mobile dunes

Sadhana ◽  
2016 ◽  
Vol 41 (9) ◽  
pp. 1019-1037
Author(s):  
Prashanth Reddy Hanmaiahgari ◽  
Ram Balachandar
Keyword(s):  
Channel Flow ◽  
Open Channel ◽  
Open Channel Flow ◽  
Turbulence Characteristics ◽  
Mobile Dunes ◽  
Non Equilibrium

scholarly journals Turbulence characteristics in sharp open-channel bends

2005 ◽  
Vol 17 (5) ◽  
pp. 055102 ◽  
Author(s):  
K. Blanckaert ◽  
H. J. de Vriend
Keyword(s):  
Open Channel ◽  
Turbulence Characteristics

scholarly journals Coral Reef Drag Coefficients – Water Depth Dependence

2017 ◽  
Vol 47 (5) ◽  
pp. 1061-1075 ◽  
Author(s):  
S. J. Lentz ◽  
K. A. Davis ◽  
J. H. Churchill ◽  
T. M. DeCarlo
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Drag Coefficient ◽  
Water Depth ◽  
Open Channel ◽  
Momentum Balance ◽  
Laboratory Studies ◽  
Drag Coefficients ◽  
Significant Term ◽  
The Cross

AbstractA major challenge in modeling the circulation over coral reefs is uncertainty in the drag coefficient because existing estimates span two orders of magnitude. Current and pressure measurements from five coral reefs are used to estimate drag coefficients based on depth-average flow, assuming a balance between the cross-reef pressure gradient and the bottom stress. At two sites wind stress is a significant term in the cross-reef momentum balance and is included in estimating the drag coefficient. For the five coral reef sites and a previous laboratory study, estimated drag coefficients increase as the water depth decreases consistent with open channel flow theory. For example, for a typical coral reef hydrodynamic roughness of 5 cm, observational estimates, and the theory indicate that the drag coefficient decreases from 0.4 in 20 cm of water to 0.005 in 10 m of water. Synthesis of results from the new field observations with estimates from previous field and laboratory studies indicate that coral reef drag coefficients range from 0.2 to 0.005 and hydrodynamic roughnesses generally range from 2 to 8 cm. While coral reef drag coefficients depend on factors such as physical roughness and surface waves, a substantial fraction of the scatter in estimates of coral reef drag coefficients is due to variations in water depth.

scholarly journals TURBULENCE CHARACTERISTICS IN ADVERSE WIND-DRIVEN OPEN-CHANNEL FLOWS

2005 ◽  
Vol 49 ◽  
pp. 505-510
Author(s):  
Iehisa NEZU ◽  
Kouichi TARUI ◽  
Keisuke YOSHIDA
Keyword(s):  
Open Channel ◽  
Channel Flows ◽  
Open Channel Flows ◽  
Turbulence Characteristics

Roughness Effects on the Mixing Properties in Open Channel Turbulent Boundary Layers

2004 ◽  
Vol 126 (6) ◽  
pp. 1025-1032 ◽  
Author(s):  
Mark F. Tachie ◽  
Donald J. Bergstrom ◽  
Ram Balachandar
Keyword(s):  
Surface Roughness ◽  
Boundary Layers ◽  
Open Channel ◽  
Turbulent Boundary Layers ◽  
Turbulence Structure ◽  
Roughness Effects ◽  
Mixing Properties ◽  
Roughness Elements ◽  
Specific Geometry ◽  
Transport And Mixing

This paper investigates the effects of surface roughness on the transport and mixing properties in turbulent boundary layers created in an open channel. The measurements were obtained on a smooth and two different types of rough surfaces using a laser Doppler anemometer. The results show that surface roughness enhances the levels of the turbulence kinetic energy, turbulence production, and diffusion over most of the boundary layer. The distributions of the eddy viscosity and mixing length are also strongly modified by surface roughness. Furthermore, the extent to which surface roughness modifies the turbulence structure depends on the specific geometry of the roughness elements.

Turbulence characteristics in plane co-jet flow in an open channel

1977 ◽  
Vol 12 (2) ◽  
pp. 311-314
Author(s):  
Yu. V. Vinogradov ◽  
V. N. Gruzdev ◽  
V. F. Postnov ◽  
A. V. Talantov
Keyword(s):  
Open Channel ◽  
Jet Flow ◽  
Turbulence Characteristics

scholarly journals Investigations on Large-Scale Geometric Roughness Elements in Open Channels with Different Heights

2021 ◽  
Vol 28 (1) ◽  
pp. 07-14
Author(s):  
Iman A. Alwan ◽  
Riyadh Z. Azzubaidi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Free Surface ◽  
Large Scale ◽  
Open Channel ◽  
Control Case ◽  
Hydraulic Characteristics ◽  
Roughness Elements ◽  
Computational Fluid Dynamics Cfd ◽  
Effective Case

Large-scale geometric roughness elements is one of the solutions that is used to protect openchannels from erosion. It is use to change the hydraulic characteristics of the flow. It may be concrete blocksor large stone placed at the bed of the channel to impose more resistance in the bed. The height of theseroughness elements is an important parameter that can affect the hydraulic characteristics of the flow. Usinga series of tests of T-shape roughness elements at three different heights, 3, 4.5, and 6cm, arranged in thefully rough configuration in order to investigate the velocity distributions along the flume. ANSYSParametric Design Language, APDL, and Computational Fluid Dynamics, CFD, were used to simulate theflow in an open channel with roughness elements. This simulation helps to find the best height of roughnesselements that can be used to change the hydraulic characteristics of the flow. The results showed that thevelocity values are decreased near the bed by about 61%, 58%, and 64% in case of 3cm, 4.5cm, and 6cmroughness heights consequently compared with the velocity of the control case. The velocity values areincreased near the free surface by about 32% and 19% in case of roughness elements height 6cm comparedwith 3cm and 4.5cm roughness heights respectively. The case of 6cm roughness height is considered to bethe effective case for decreasing the velocity values near the bed of the flume.

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