Three-dimensional Tidal-flow Numerical Study Of The Impact Of Pollutant Movement By Artificial Island In The Gulf

The gulf as a semi-enclosed sea area, the construction of artificial island drastically change the hydrodynamic characteristics of the area, and lead to the flow field restructuring in the gulf, the diffusion regularity of pollutant become more complex. In order to avoid the construction of artificial island causing heavily deterioration of the environment, it’s necessary to simulate and predict the movement of pollutant in feasibility study stage, afterwards study the impact of water environment by artificial island.Based on EOMSED, taking Dalian bay as research background, this paper establish a three-dimensional tidal current model of the gulf, complete the validation of the tidal flow filed. Analyze the change of the flow field with the artificial island is embedded or not, the study shows that after constructed artificial island, an obvious circulation flow is formed in the gulf, the flow velocity and direction change obviously. After that, through Lagrangian particle tracking technology, simulate the movement of pollutant with single particle or particle swarm separately, and then study the3-D motion regularity of pollutant before and after constructed artificial island. The results indicate that, compared with the original terrain conditions, the movement of pollutant particles change obviously after embedded artificial island, and the path of pollutant move out of the bay change from the right of the bay gap without artificial island to the left and right of it.Finally, based on the simulation of pollutant particle swarm movement, the paper define the particle average concentration of pollutant to assess the impact of water environment by the artificial island. For three kinds of artificial island, four preset positions of outfall, set the particle average concentration of pollutant as evaluation index, compare and analyze the change of the pollutant movement, recommend the planning of artificial island construction scheme, and provide suggestions for the discharging way and the site selection of outfall.