Saline intrusion into marine sewage ouffalls will greatly decrease the efficiency of sewage disposal. In order to investigate the mechanisms of this flow, in this paper, a three-dimensional numerical model based on F...Saline intrusion into marine sewage ouffalls will greatly decrease the efficiency of sewage disposal. In order to investigate the mechanisms of this flow, in this paper, a three-dimensional numerical model based on FVM （Finite Volume Method） is established, The RNG κ-ε model is selected for turbulence modeling. The time-averaged vohtme fraction equations are introduced to simulate the stratification and inteffaeial exchange of sewage and seawater in outfalls. Validity of the established three-dimensional numerical model is evaluated by comparisons of numerical results with experimental data. With this three-dimensional numerical model, the internal flow characteristics in ouffalls for different sewage discharges are simulated. The results indicate that for a low sewage discharge, saline circulates in the outfall due to intrusion and both the inflowing momentum and the inteffaeial turbulent mixing are important mechanisms to extrude the saline. For a high sewage discharge, saline intrusion could be avoided. The inflow momentum is the main mechanism to extrude the saline and the inteffacial turbulent mixing is nut important relatively. Even at a high sewage discharge, the saline wedge would be retained in the main ouffall pipe after the risers are purged. It takes a long time for this saline wedge to be extruded by interracial turbulent mixing.展开更多
Based on the study of the wave propagation, breaking, longshore current and the effect of wave on current structure in the near shore area with a mild bottom slope, the wave is considered to be an important dynamic fa...Based on the study of the wave propagation, breaking, longshore current and the effect of wave on current structure in the near shore area with a mild bottom slope, the wave is considered to be an important dynamic factor for pollutant transportation in the coastal water. Numerical simulation shows that the pollutant will transfer along shore when the incident wave is at an angle to the shoreline. This phenomenon is very significant if the outfall is located in the surfzone. Therefore, in the design of sea outfall, to improve near shore environment, the water wave should be considered as an important hydrodynamic factor.展开更多
文摘Saline intrusion into marine sewage ouffalls will greatly decrease the efficiency of sewage disposal. In order to investigate the mechanisms of this flow, in this paper, a three-dimensional numerical model based on FVM （Finite Volume Method） is established, The RNG κ-ε model is selected for turbulence modeling. The time-averaged vohtme fraction equations are introduced to simulate the stratification and inteffaeial exchange of sewage and seawater in outfalls. Validity of the established three-dimensional numerical model is evaluated by comparisons of numerical results with experimental data. With this three-dimensional numerical model, the internal flow characteristics in ouffalls for different sewage discharges are simulated. The results indicate that for a low sewage discharge, saline circulates in the outfall due to intrusion and both the inflowing momentum and the inteffaeial turbulent mixing are important mechanisms to extrude the saline. For a high sewage discharge, saline intrusion could be avoided. The inflow momentum is the main mechanism to extrude the saline and the inteffacial turbulent mixing is nut important relatively. Even at a high sewage discharge, the saline wedge would be retained in the main ouffall pipe after the risers are purged. It takes a long time for this saline wedge to be extruded by interracial turbulent mixing.
基金This work was supported by Key Project of the National Natural Science Foundation of China (Grant No. 59839330).
文摘Based on the study of the wave propagation, breaking, longshore current and the effect of wave on current structure in the near shore area with a mild bottom slope, the wave is considered to be an important dynamic factor for pollutant transportation in the coastal water. Numerical simulation shows that the pollutant will transfer along shore when the incident wave is at an angle to the shoreline. This phenomenon is very significant if the outfall is located in the surfzone. Therefore, in the design of sea outfall, to improve near shore environment, the water wave should be considered as an important hydrodynamic factor.
