A model to calculate the concentration of organic pollutant in the water column is presented. The inflow, outflow, adsorption of pollutant to the suspended particles and settling of particles, diffusion across the s...A model to calculate the concentration of organic pollutant in the water column is presented. The inflow, outflow, adsorption of pollutant to the suspended particles and settling of particles, diffusion across the sediment water interface, and volatilization to the atmosphere were considered in this model. Dynamic simulation experiment of pentachlorophenol(PCP) has been made in the laboratory. The model parameters were also estimated with experimental data(diffusion mass transfer coefficient, 0.00112m/d; net settling velocity of particles, 0.323 m.d -1 ; volatilization rate constant, 1.94×10 -4 d -1 ). There are little differences between calculated values and measured values. Adsorption of pollutant to the particles and settling of particles are very important mechanisms for removal of organic pollutant from the water. The principles and methods of this model are also applicable to the prediction of the concentration of other trace elements and organic constituents in aquatic systems.展开更多
This paper presents numerical simulations of dam-break flow over a movable bed. Two different mathematical models were compared: a fully coupled formulation of shallow water equations with erosion and deposition terms...This paper presents numerical simulations of dam-break flow over a movable bed. Two different mathematical models were compared: a fully coupled formulation of shallow water equations with erosion and deposition terms(a depth-averaged concentration flux model), and shallow water equations with a fully coupled Exner equation(a bed load flux model). Both models were discretized using the cell-centered finite volume method, and a second-order Godunov-type scheme was used to solve the equations. The numerical flux was calculated using a Harten, Lax, and van Leer approximate Riemann solver with the contact wave restored(HLLC). A novel slope source term treatment that considers the density change was introduced to the depth-averaged concentration flux model to obtain higher-order accuracy. A source term that accounts for the sediment flux was added to the bed load flux model to reflect the influence of sediment movement on the momentum of the water. In a onedimensional test case, a sensitivity study on different model parameters was carried out. For the depth-averaged concentration flux model,Manning's coefficient and sediment porosity values showed an almost linear relationship with the bottom change, and for the bed load flux model, the sediment porosity was identified as the most sensitive parameter. The capabilities and limitations of both model concepts are demonstrated in a benchmark experimental test case dealing with dam-break flow over variable bed topography.展开更多
This paper is devoted to the study of the existence of weak solution in time with a periodic domain of sediment transport model. We consider a one-dimensional viscous sediment transport model which combines a viscous ...This paper is devoted to the study of the existence of weak solution in time with a periodic domain of sediment transport model. We consider a one-dimensional viscous sediment transport model which combines a viscous Shallow-Water system with a transport equation that describes the bottom evolution. The model studied does not take into account all the regularizing terms used by Roamba Brahima, Zongo Yacouba and Jean de Dieu Zabsonré (2017) and we use a better transport equation than that used by Zabsonré (2012).展开更多
通过将SWMM(storm water management model)模型与底泥输运模型耦合计算实现对于排水管网底泥输运工况的模拟。利用该耦合求解方法,底泥输运过程对于管渠过流断面以及水流中污染物浓度的影响均可进行定量计算。耦合计算过程中全局时间...通过将SWMM(storm water management model)模型与底泥输运模型耦合计算实现对于排水管网底泥输运工况的模拟。利用该耦合求解方法,底泥输运过程对于管渠过流断面以及水流中污染物浓度的影响均可进行定量计算。耦合计算过程中全局时间步长由SWMM的时间步长确定,通过对底泥输运模型进行适当的调整使其适应SWMM时间步长,从而实现模拟的数值稳定性,避免了底泥输运模型出现过度沉积或过度冲刷引起数值不稳定的情况。该模拟方法通过2个案例进行了验证。通过案例的模拟结果可以看出该耦合过程可以给出稳定且合理的模拟结果,可以模拟管渠底泥的沉积及冲刷的过程以及其对于管渠过流断面及污染物浓度变化的影响。相较于单纯的SWMM模拟结果,耦合模型可以给出更加准确的模拟结果。展开更多
文摘A model to calculate the concentration of organic pollutant in the water column is presented. The inflow, outflow, adsorption of pollutant to the suspended particles and settling of particles, diffusion across the sediment water interface, and volatilization to the atmosphere were considered in this model. Dynamic simulation experiment of pentachlorophenol(PCP) has been made in the laboratory. The model parameters were also estimated with experimental data(diffusion mass transfer coefficient, 0.00112m/d; net settling velocity of particles, 0.323 m.d -1 ; volatilization rate constant, 1.94×10 -4 d -1 ). There are little differences between calculated values and measured values. Adsorption of pollutant to the particles and settling of particles are very important mechanisms for removal of organic pollutant from the water. The principles and methods of this model are also applicable to the prediction of the concentration of other trace elements and organic constituents in aquatic systems.
文摘This paper presents numerical simulations of dam-break flow over a movable bed. Two different mathematical models were compared: a fully coupled formulation of shallow water equations with erosion and deposition terms(a depth-averaged concentration flux model), and shallow water equations with a fully coupled Exner equation(a bed load flux model). Both models were discretized using the cell-centered finite volume method, and a second-order Godunov-type scheme was used to solve the equations. The numerical flux was calculated using a Harten, Lax, and van Leer approximate Riemann solver with the contact wave restored(HLLC). A novel slope source term treatment that considers the density change was introduced to the depth-averaged concentration flux model to obtain higher-order accuracy. A source term that accounts for the sediment flux was added to the bed load flux model to reflect the influence of sediment movement on the momentum of the water. In a onedimensional test case, a sensitivity study on different model parameters was carried out. For the depth-averaged concentration flux model,Manning's coefficient and sediment porosity values showed an almost linear relationship with the bottom change, and for the bed load flux model, the sediment porosity was identified as the most sensitive parameter. The capabilities and limitations of both model concepts are demonstrated in a benchmark experimental test case dealing with dam-break flow over variable bed topography.
文摘This paper is devoted to the study of the existence of weak solution in time with a periodic domain of sediment transport model. We consider a one-dimensional viscous sediment transport model which combines a viscous Shallow-Water system with a transport equation that describes the bottom evolution. The model studied does not take into account all the regularizing terms used by Roamba Brahima, Zongo Yacouba and Jean de Dieu Zabsonré (2017) and we use a better transport equation than that used by Zabsonré (2012).
文摘通过将SWMM(storm water management model)模型与底泥输运模型耦合计算实现对于排水管网底泥输运工况的模拟。利用该耦合求解方法,底泥输运过程对于管渠过流断面以及水流中污染物浓度的影响均可进行定量计算。耦合计算过程中全局时间步长由SWMM的时间步长确定,通过对底泥输运模型进行适当的调整使其适应SWMM时间步长,从而实现模拟的数值稳定性,避免了底泥输运模型出现过度沉积或过度冲刷引起数值不稳定的情况。该模拟方法通过2个案例进行了验证。通过案例的模拟结果可以看出该耦合过程可以给出稳定且合理的模拟结果,可以模拟管渠底泥的沉积及冲刷的过程以及其对于管渠过流断面及污染物浓度变化的影响。相较于单纯的SWMM模拟结果,耦合模型可以给出更加准确的模拟结果。
