Determination of Substrate ShearSstress and Current Energy Around Impervious Angular Obstacles and all Kinds of Permeable Barriers in the Direct Channel with Moving Bed

Document Type : Research Article

Authors

1 Faculty of Engineering, Bu-Ali Sina University of Hamedan

2 Assistant Professor, Civil Engineering Department, Faculty of Engineering, Bu-Ali Sina University, Hamedan, Iran

Abstract

Abstract -
Shear stress on the floor and walls of rivers and channels is one of the most important parameters of open-air flows. The presence of barriers in the flow path causes significant changes in the shear stress distribution on the channel and river floor. In the preliminary research, the distribution of shear stresses around impervious angular barriers and permeable angular barriers of Gabion and double rod with two cases along with zigzag have been presented. The results are presented using extracted laboratory data. The experiments were carried out in a rectangular channel with a Froud number of 0.26 under clear water conditions and the threshold of motion of the particles of the floor. The experiments were carried out by placing obstacles at angles of 135 and 45 degrees relative to the flow path. In this study, depth-Average velocity method was used to calculate shear stress. Also, the kinetic energy of the total flow through each section in the sections before and after each obstacle was calculated and the kinetic energy depreciation was calculated due to the presence of various obstacles. The results show that the shear stress distribution of the substrate in the impervious barrier of shear stress is higher in permeable barrier permeability with 30% porosity. Also, in permeable barriers, the two-row rod along the zigzag and the shear stress distribution are approximately similar, so that the effect of the geometric arrangement of the bars on the shear stress distribution on the floor is not high and the performance of the barrier barriers is two The row is close to each other. In comparison with energy depreciation, the results also show that energy depreciation in Impervious barriers is more than permeable barriers, and in the case of permeable barriers with the same opening percentages, energy depreciation in lattice barriers is more than barrier barriers Regardless of their geometric arrangement, they relate to barrier angles of energy deformation to the geometric arrangement of bars, as the zigzag bar barrier barriers along with the obstacles along the way depreciate more energy.

Keywords

References

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History

  • Receive Date: 07 November 2017
  • Revise Date: 16 June 2018
  • Accept Date: 18 June 2018

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