Investigation of bed Stability in Downstream for the Diversion dam under Scour (Mill & Moghan case study)

Gorji, Faeze | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 45879 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Shamsai, Abolfazl
  7. Abstract:
  8. Numerical simulations and large eddy simulations (LES) of turbulent flow downstream of diversion dam , pool-riffle bedform in different geometrical ratios (different lengths of riffle and pool) with flow Reynolds number of 3.0 E+04 to 3.3E+04, downstream of special case study "Mill and Moghan diversion dam" with Froude number of 0.5 are presented The calculations are performed using a computational fluid dynamics model, FLOW-3D, which solves the Navier-Stokes equations in three dimensions with finite volume method. Numerical simulations are validated by comparing the numerical results of time-averaged flow patterns downstream of pool-riffle sequence with that of the experimental measurements. At the downstream of pool, flow turbulence with the use of Y-vorticity is shown. The maximum values of bed shear stresses at the downstream of pool in different length of pool and riffle are compared and turbulent structures are studied by using the Q criterion. Owing to the turbulent conditions and oscillations of flow, all of contours are extracted at the moment that the highest shear stress is exerted at the bed (Critical moment). Interactions of horseshoe vortices on different cases of pools geometry are studied. Numerical results show that the critical arrangement for which the largest bed shear stress was observed is the case with the width per total ratio 6.4
  9. Keywords:
  10. Flow Patterns ; Turbulent Flow ; Diversion Dam ; Bed Scour

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