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The Experimental Investigation of Lateral Dispersion In Vegetated Flow

Shoaei, Farrokh | 2009

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 40593 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Jamali, Mirmosadegh
  7. Abstract:
  8. There is an importance issue for preservation and survival of ecological systems by vegetation. A study focusing on the hydrodynamics of these complex ecosystems could help to explain the filtering ability of vegetation in wetlands and estuaries. Wetlands assist in flood control, shoreline protection, and groundwater recharge.In addition, they play a purification role, removing sediments and contaminants from polluted waters, nutrient uptake, and oxygen production. Laboratory experiments have been designed to study the influence of marsh vegetation on lateral dispersion. The flow through vegetation is modeled by a circulating flow going through an array of plastic dowels in an experimental flume. The study included flow discharges ranging from laminar to turbulent (90≤Red<400) and dowel densities ranging from sparse to dense (0.009≤Φ≤0.035). The lateral dispersion coefficient, Dy, has been estimated by releasing dye upstream of the array and measuring time series of concentration downstream of the array using image processing technique. The purpose of the present work was to estimate the required spatial and temporal scale for developing the lateral dispersion in vegetated flow. For Red<200, Experimental results indicate a decrease in non-dimensional lateral dispersion coefficients with increase of Reynolds number in channel flow. Theoretical prediction which is defined for uniform density and both laminar and turbulent flow has good consistency with experimental results of this study.
  9. Keywords:
  10. Reynolds Number ; Lateral Dispersion Coefficient ; Emergent Vegetation ; Stems Density Coefficient

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