A set of hydrostatic atmospheric thermodynamic equations and diffusion equation are solved numerically to simulate the flow,temperature and concentration fields over the Fenhe River Valley,Shanxi Province. The results...A set of hydrostatic atmospheric thermodynamic equations and diffusion equation are solved numerically to simulate the flow,temperature and concentration fields over the Fenhe River Valley,Shanxi Province. The results are compared with the data observed in a tracer experiment carried out in February of 1984. The concentration distributions are calculated by three approaches:ordinary grid numerical model,nested grid model and Gaussian model.The comparison shows that the nested grid model gives the best results and needs only a little more computer time.展开更多
We present a new Dirichlet boundary condition for the rate-type non-Newtonian diffusive constitutive models. The newly proposed boundary condition is compared with two such well-known and popularly used boundary condi...We present a new Dirichlet boundary condition for the rate-type non-Newtonian diffusive constitutive models. The newly proposed boundary condition is compared with two such well-known and popularly used boundary conditions as the pure Neumann condition and the Dirichlet condition by Sureshkumar and Beris. Our condition is demonstrated to be more stable and robust in a number of numerical test cases. A new Dirichlet boundary condition is implemented in the framework of the finite difference Marker and Cell （MAC） method. In this paper, we also present an energy-stable finite difference MAC scheme that preserves the positivity for the conformation tensor and show how the addition of the diffusion helps the energy-stability in a finite difference MAC scheme-setting.展开更多
文摘A set of hydrostatic atmospheric thermodynamic equations and diffusion equation are solved numerically to simulate the flow,temperature and concentration fields over the Fenhe River Valley,Shanxi Province. The results are compared with the data observed in a tracer experiment carried out in February of 1984. The concentration distributions are calculated by three approaches:ordinary grid numerical model,nested grid model and Gaussian model.The comparison shows that the nested grid model gives the best results and needs only a little more computer time.
文摘We present a new Dirichlet boundary condition for the rate-type non-Newtonian diffusive constitutive models. The newly proposed boundary condition is compared with two such well-known and popularly used boundary conditions as the pure Neumann condition and the Dirichlet condition by Sureshkumar and Beris. Our condition is demonstrated to be more stable and robust in a number of numerical test cases. A new Dirichlet boundary condition is implemented in the framework of the finite difference Marker and Cell （MAC） method. In this paper, we also present an energy-stable finite difference MAC scheme that preserves the positivity for the conformation tensor and show how the addition of the diffusion helps the energy-stability in a finite difference MAC scheme-setting.
