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Numerical Simulation of Hydrodynamics of Flow over Gabion Stepped Weir

Mousavi Khomeyrani, Zahra | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55065 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Shamsai, Abolfazl; Ghaemian, Mohsen
  7. Abstract:
  8. The use of stepped weirs dates back at least 3500 years. In this research, the hydrodynamics of gabion stepped weirs have been investigated as a three-dimensional simulation of two-phase flow air-water using Flow3D software and the method of computational fluid dynamics (CFD) analysis. In order to solve the Reynolds-Averaged Navier-Stokes (RANS) equations, the RNG turbulence model (k-ε) was used and the free surface elevation of fluid was determined by the volume of fluid (VOF) method. The experimental results of Wutrish and Chanson (2014) over gabion stepped weirs are used to validate the numerical model simulations. Gabion stepped weirs with steps of 3, 7.5, and 10 cm in height, as well as downstream slopes of 26.6, 45, 53, and 60 degrees were evaluated. The drag coefficients of the porous media were determined using sensitivity analysis. The energy dissipation and velocity at the downstream end of weir, the pressure distributions in the gabion steps, and the location of inception point of free-surface aeration were investigated, and also a suitable equation was presented to determine the Li parameter as the distance between the edge of the first step and the location of inception point of free-surface aeration at the gabion stepped weir. The results showed that by increasing the height of the steps from 3 to 7.5 and 10 cm, the amount of energy dissipation increases to 9.45 and 14.88%, respectively. Additionally, it was found that with increasing the amount of porosity from 0.375 to 0.4375 and 0.5, the amount of maximum pressure in the eighth gabion step increased to 4.47 and 16.29%, respectively
  9. Keywords:
  10. Two Phase Flow ; Turbulence Model ; Computational Fluid Dynamics (CFD) ; Numerical Simulation ; Volume of Fluid ; Reynolds Average Navier-Stocks (RANS)Method ; Gabion Stepped Spillway

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