A three-dimensional mathematical model was developed to simulate the pollutant removal efficiency of the soil and plants in the pot test. The advection, dispersion, diffusion, adsorption, biochemical reaction and plan...A three-dimensional mathematical model was developed to simulate the pollutant removal efficiency of the soil and plants in the pot test. The advection, dispersion, diffusion, adsorption, biochemical reaction and plant uptake processes were taken into account in the model. The three-dimensional modified Richards equation was used in simulating flow field. The mass balance law was employed in deriving the equation for pollutant transport, where the diffusion and dispersion were described with the Fick-type law, the adsorption was macroscopically expressed as form isotherm, and the bio-chemical degradation process was assumed to follow the Monod kinetics. The mathematical model was descretized by the finite element numerical method. In the pot test, the hydraulic loading was assumed to have the intermittent pattern simulating the rainfall duration and the occurrence of frequency, and the concentrations of pollutants in the influent and effluent were measured. The computed overall removal rates for the CODCr and TN in four cases are in the range of 90.62% - 95.43% and 85.01% - 96.46%, respectively. The differences between the computed and tested overall removal rates for the CODCr and TN are smaller than 5%. The time-varying oscillation pattern of the concentrations of the CODCr and TN were rationally simulated, which showed that the model presented in this article could be used to assess the pollutant removal efficiency of the soil and plants in related cases.展开更多
This paper deals with the 2—D numerical simulation of non-linear waves behind the stern of a flat-bottomed ship.The fluid is assumed inviscid and imcompressible.Fully non-linear dynamic and kinematic boundary condi- ...This paper deals with the 2—D numerical simulation of non-linear waves behind the stern of a flat-bottomed ship.The fluid is assumed inviscid and imcompressible.Fully non-linear dynamic and kinematic boundary condi- tions are applied on free surface,and suitable radiation condition is applied at outflow boundary.Time-dependent stream functions are used as the dependent variables to approach the steady state solution.Finite difference meth- ods and body-fitted coordinates are employed to obtain the numerical solution.Physical tests with a schematized flat-bottomed ship model are performed to validate the computational scheme.Results from both computations and experiments seem to be in reasonable agreement.展开更多
基金supported by the Natural Science Foundation of Hohai University (Grant No. 2008427511)
文摘A three-dimensional mathematical model was developed to simulate the pollutant removal efficiency of the soil and plants in the pot test. The advection, dispersion, diffusion, adsorption, biochemical reaction and plant uptake processes were taken into account in the model. The three-dimensional modified Richards equation was used in simulating flow field. The mass balance law was employed in deriving the equation for pollutant transport, where the diffusion and dispersion were described with the Fick-type law, the adsorption was macroscopically expressed as form isotherm, and the bio-chemical degradation process was assumed to follow the Monod kinetics. The mathematical model was descretized by the finite element numerical method. In the pot test, the hydraulic loading was assumed to have the intermittent pattern simulating the rainfall duration and the occurrence of frequency, and the concentrations of pollutants in the influent and effluent were measured. The computed overall removal rates for the CODCr and TN in four cases are in the range of 90.62% - 95.43% and 85.01% - 96.46%, respectively. The differences between the computed and tested overall removal rates for the CODCr and TN are smaller than 5%. The time-varying oscillation pattern of the concentrations of the CODCr and TN were rationally simulated, which showed that the model presented in this article could be used to assess the pollutant removal efficiency of the soil and plants in related cases.
文摘This paper deals with the 2—D numerical simulation of non-linear waves behind the stern of a flat-bottomed ship.The fluid is assumed inviscid and imcompressible.Fully non-linear dynamic and kinematic boundary condi- tions are applied on free surface,and suitable radiation condition is applied at outflow boundary.Time-dependent stream functions are used as the dependent variables to approach the steady state solution.Finite difference meth- ods and body-fitted coordinates are employed to obtain the numerical solution.Physical tests with a schematized flat-bottomed ship model are performed to validate the computational scheme.Results from both computations and experiments seem to be in reasonable agreement.
