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The Study of Currents Caused by the Sunlight in Coastal Areas with Submerged and Emergent Vegetation

Mousazadeh Darzi, Fatereh | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 50295 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Jamali, Mirmosadegh
  7. Abstract:
  8. Aqueous environment with vegetation in coastal areas plays important role in ecologic systems. The plants in aqueous environment caused to vertical and lateral changes of flow velocity profile. When sunlight penetrates the water, it will turns into heat energy. The plants caused to blocking the light path, to make a difference in temperature and thus the density differences on the horizon. This density gradient will lead to the gravity flow. Due to the observations, in coastal wetlands, beside the plants the emerged from the water, there are some completely submerged plants that their root in the soil and shallow layer of fluid covered on them. This study to approaching the conditions, is discussed the currents in the combinational case of submerged and emergent vegetation.To study this case, the laboratory modeling has been used. To perform the modeling of emergent and submerged vegetation, the rigid rods and artificial plants have been used respectively. Also the created currents such as velocity speed and field, condensed current exchange based on the submerge rate and plant condensation as well as the effect of submerged plants on current have been discussed. To obtain the velocity, the PIV image processing technique has applied. So the current velocity is increased because of the loss of water depth due to the presence of submerged vegetation, then the coming current depth has been decreased and also it was seen in low condensations, the backing currents has passed over the submerged vegetation and the increasing condensation will lead to the more uniform of backing currents. The speed and discharge of reciprocal currents in increasing condensation will decrease because of increasing drag force. In other hand, we found the more closer to the submerged vegetation, the more current tendency to pass over the submerged vegetation region. In fact the more closer to the submerged vegetation area, the effect of submerged vegetation is more evident. This research, the effect of fluid height on velocity profile has been studied. The increasing fluid height will lead to the increasing interaction flow and decreasing of the coming current. Maximum velocity of backing current has tilted upward and also the velocity of backing current in the bottom parts of receiver is insignificant because of the effect of the vegetation presence. Actually, the increasing fluid height caused the current in the submerged vegetation area to be approached to zero and the reciprocal current has transferred to the upper of submerged vegetation. All results are compared in experiments with the numerical models and provided in chapter 6
  9. Keywords:
  10. Emergent Vegetation ; Sunlight ; Image Processing ; Aquatic Media ; Exchange Flow ; Submerged Vegetation ; Coastal Areas

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