Effect of the aspect ratio on the velocity field of a straight open-channel flow

2021 ◽  
Vol 33 (8) ◽  
pp. 085110
Author(s):  
A.-M. Shinneeb ◽  
G. Nasif ◽  
R. Balachandar
Keyword(s):  
Velocity Field ◽  
Aspect Ratio ◽  
Channel Flow ◽  
Open Channel ◽  
Open Channel Flow

Hydraulics of offset baffle culvert fishways

1988 ◽  
Vol 15 (6) ◽  
pp. 1043-1051 ◽  
Author(s):  
N. Rajaratnam ◽  
C. Katopodis ◽  
S. Lodewyk
Keyword(s):  
Experimental Study ◽  
Velocity Field ◽  
Turbulent Flow ◽  
Key Words ◽  
Channel Flow ◽  
Open Channel ◽  
Open Channel Flow ◽  
Flow Equation

This paper presents the results of an experimental study on the hydraulics of culverts with offset baffles to pass fish. Using analytical considerations and experimental observations, a flow equation has been developed between the discharge, diameter, depth, and slope for a culvert fish way with the standard offset baffle system. The velocity field at the slot has also been evaluated. Some further experiments were performed to assess the effect of baffle spacing and height on the hydraulics of the culvert fishway. Key words: culverts, fishways, baffles, hydraulics, open-channel flow, turbulent flow.

scholarly journals Effect of aspect ratio on higher order moments of velocity fluctuations in hydraulically rough open channel flow

2018 ◽  
Vol 40 ◽  
pp. 05045
Author(s):  
Minakshee Mahananda ◽  
Prashanth Reddy Hanmaiahgari
Keyword(s):  
Aspect Ratio ◽  
Order Statistics ◽  
Channel Flow ◽  
Open Channel ◽  
Outer Region ◽  
Open Channel Flow ◽  
Higher Order ◽  
Higher Order Statistics ◽  
Velocity Fluctuations ◽  
Bed Roughness

The effect of aspect ratio on the higher order statistics of velocity fluctuations in a hydraulically rough turbulent open channel flow is investigated. In this regard, an experiment was conducted in a rough bed narrow open channel flow of aspect ratio equal to three and the instantaneous flow velocities were measured using a Nortek Vectrino+ Acoustic Doppler Velocimeter. To understand the effect of aspect ratio, the results obtained from the present study are compared with the literature data of approximately same Reynolds number and bed roughness in a wide open channel flow for turbulence intensities and higher order statistics of velocity fluctuations. Comparison of turbulence intensities between Narrow OCF and Wide OCF shows occurrence of higher streamwise and vertical turbulence intensities in the outer region of Narrow OCF. The results of third order moments of velocity fluctuations are sensitive to aspect ratio in the outer region.

Effect of aspect ratio on developing and developed narrow open channel flow with rough bed

2018 ◽  
Vol 45 (9) ◽  
pp. 780-794 ◽  
Author(s):  
Minakshee Mahananda ◽  
Prashanth Reddy Hanmaiahgari ◽  
Ram Balachandar
Keyword(s):  
Kinetic Energy ◽  
Aspect Ratio ◽  
Channel Flow ◽  
Open Channel ◽  
Reynolds Shear Stress ◽  
Open Channel Flow ◽  
Flow Region ◽  
Channel Flows ◽  
Open Channel Flows ◽  
Rough Bed

This study attempts to unravel the effect of aspect ratio on the turbulence characteristics in developing and fully developed narrow open channel flows. In this regard, experiments were conducted in a rough bed open channel flow. Instantaneous 3D velocities were acquired using an acoustic Doppler velocimeter at various locations along the centerline of the flume. The variables of interest include the mean components of the flow velocity, turbulence intensity, wall normal Reynolds shear stress, correlation coefficient, turbulence kinetic energy, and anisotropy. A new correlation between the equivalent roughness and velocity shift from the smooth wall logarithmic equation as a function of aspect ratio is proposed. Aspect ratio was found to influence the velocity characteristics throughout the depth in the developing flow region, while the effects are confined to the outer layer for fully developed flows. New equations to describe the variation of turbulence intensities and turbulent kinetic energy are proposed for narrow open channel flows. Reynolds stress anisotropy analysis reveals that level of anisotropy in narrow open channel flow is less than in wide open channel flows. Finally, a linear regression model is proposed to predict flow development length in narrow open channel flows with a rough bed.

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