Hakata Bay, Two-dimensional Hydrodynamic And Dispersion Of Pollutants Transport In The Numerical Simulation

As the developing of modern industry in coastal zone, the coastal environment is deteriorated badly. In estuaries and coastal seas, the tidal flow is a basic hydrodynamic factor, which affects other substance movement remarkably, such as sand, salinity and so on. To research the environmental problems of estuaries and coastal seas, we must learn the tidal flow field in detail firstly. The numerical simulation is an effective method.The main task of this dissertation is to establish a hydrodynamic and pollutant transport model, and to simulate the tide field and concentration field of Hakata Bay:(1) Dispersing the long-wave equation on interlaced grid by ADI method, a two-dimension hydrodynamic model is established to simulate the tidal flow in Hakata Bay under the effects of M₂,S₂,O₁,K₁ tide.(2) The tidal residual current is weak, but it plays an important role in the transport and long-term distribution of pollutants. In this dissertation, the tidal residual current is calculated under the effect of M₂ tide.(3) Basing on the hydrodynamic model, a numerical model is established to simulate the transport and dispersion of pollutants in the coastal waters. The model is applied to simulate the COD distribution in Hakata Bay.(4) To learn the rationality of the hydrodynamic and pollutant transport model intuitively, the visualization of the tidal field and concentration field is an effective approach. The paper basically gets this goal by a simple processing system.(5) Discuss some mathematical models of the pollutant transport problems in some local river flow fields. By integral transform method, the paper establishes the usual finite difference approximation scheme to solve the numerical solutions and gives examples for the computation of the approximating solutions, moreover, discusses one-dimensional characteristic finite difference method for a convection-diffusion equation under usual conditions.