Three-dimensional Water Temperature and Hydrodynamic Simulation of Xiangxi River Estuary

摘要

When the impoundment of the Three Gorges Reservoir begins, the water level rises, and the water flow rate slows down, thus the residence time of bay and tributary pollutant extends, and the water environment changes significantly, resulting in different degrees of cyanobacteria outbreak in each spring. Numerous studies show that nutrient concentrations in mainstream is relatively higher than in tributary, so stratified density current of mainstreams and tributaries has played a key role on Bay eutrophication. In order to investigate the exchange process of mainstreams and tributaries, set boundary conditions according to the observed data, and then simulate Xiangxi estuary three-dimensional hydrodynamic characteristics by using Flow-3D software, which can simulate it well. The model theoretically confirms that the intrusion density current phenomenon does exist in typical tributaries, and the simulation results show that near the estuary region, there is a big diversity in the temperature field and the flow field along the transverse distribution, but when the estuary distance increases, the flow field in the cross section, except for a small area near the riverbank, tends to be in a mean state along the transverse distribution.