Turbulent characteristics of flow in the vicinity of mid-channel braid bar

2020 ◽  
Author(s):  
Mohammad Amir Khan ◽  
Nayan Sharma ◽  
MANISH PANDEY ◽  
Mohd Obaid Qamar
Keyword(s):  
Turbulent Flow ◽  
Flow Structure ◽  
Turbulent Intensity ◽  
Flow Area ◽  
Fluvial Processes ◽  
Relative Dominance ◽  
Turbulent Characteristics ◽  
Turbulent Flow Structure ◽  
The Impact ◽  
Channel Bar

The impact of a mid-channel bar on the turbulent flow structure has been investigated in this research. A new Dominance Function S_(i,H) is proposed in this study as a measure of the relative dominance of ejection and sweep events in turbulent flow structure. Occurrence of the kolk-boil phenomenon is observed due to interaction of ejection and sweep events.. A new parameter Movement Ratio is formulated in this study which is found to faithfully reflect the fluvial processes of sedimentation and scouring on the channel bed.. Acceleration of flow is seen to occur at adjoining regions close to the upstream end of the bar. Due to the presence of the bar, the flow area in its proximity decreases which has caused increment in the velocity at sections located near the upstream end of the mid-channel bar. For model runs with bars, a distinct bulge in the turbulent intensity graph is observed.

scholarly journals Turbulent flow structure at a 90-degree open channel confluence: Accounting for the distortion of the shear layer

2016 ◽  
Vol 12 ◽  
pp. 130-147 ◽  
Author(s):  
Saiyu Yuan ◽  
Hongwu Tang ◽  
Yang Xiao ◽  
Xuehan Qiu ◽  
Huiming Zhang ◽  
...  
Keyword(s):  
Turbulent Flow ◽  
Shear Layer ◽  
Flow Structure ◽  
Open Channel ◽  
Turbulent Flow Structure ◽  
Channel Confluence

Turbulent flow structure at a discordant river confluence: Asymmetric jet dynamics with implications for channel morphology

2017 ◽  
Vol 122 (6) ◽  
pp. 1278-1293 ◽  
Author(s):  
Alexander N. Sukhodolov ◽  
Julian Krick ◽  
Tatiana A. Sukhodolova ◽  
Zhengyang Cheng ◽  
Bruce L. Rhoads ◽  
...  
Keyword(s):  
Turbulent Flow ◽  
Flow Structure ◽  
Channel Morphology ◽  
River Confluence ◽  
Turbulent Flow Structure

Effect of the Accuracy Order of the Discretization Scheme on the Prediction Performance for the Turbulent Flow Structure Inside Fuel Assembly: Sensitivity Study

2015 ◽  
Author(s):  
Gong Hee Lee ◽  
Ae Ju Cheong
Keyword(s):  
Turbulent Flow ◽  
Fuel Assembly ◽  
Flow Structure ◽  
Sensitivity Study ◽  
Higher Order ◽  
Discretization Scheme ◽  
Order Of Accuracy ◽  
Accuracy Order ◽  
Turbulent Flow Structure ◽  
Numerical Order

Spatial discretization errors result from both the numerical order of accuracy of the discretization scheme, and from grid spacing. It is well known that second, or higher, order discretization schemes are potentially able to produce high-quality solutions. In addition, when either the flow is not aligned with the grid, or is complex, it is recommended that the first order discretization scheme not be used for the convection term, if possible. However, the higher-order scheme can also result in convergence difficulties and instabilities at certain flow conditions. In this study, to examine the effect of the numerical order of accuracy of the discretization scheme on the prediction accuracy for the turbulent flow structure inside fuel assembly with the split-type mixing vanes, simulations were conducted with the commercial CFD (Computational Fluid Dynamics) software, ANSYS CFX R.14. Two different types of the discretization scheme for the convection-terms-of-momentum and -turbulence equations, i.e. 1st order upwind scheme and a high resolution scheme, were used. The predicted results were compared with the measured data from MATiS-H (Measurement and Analysis of Turbulent Mixing in Subchannles-Horizontal) facility, installed in the KAERI (Korea Atomic Energy Research Institute).

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