In this report,we give a viscosity splitting method for the Navier-Stokes/Darcy problem.In this method,the Navier-Stokes/Darcy equation is solved in three steps.In the first step,an explicit/implicit formulation is us...In this report,we give a viscosity splitting method for the Navier-Stokes/Darcy problem.In this method,the Navier-Stokes/Darcy equation is solved in three steps.In the first step,an explicit/implicit formulation is used to solve the nonlinear problem.We introduce an artificial diffusion term qDu in our scheme whose purpose is to enlarge the time stepping and enhance numerical stability,especially for small viscosity parameter n,by choosing suitable parameter q.In the second step,we solve the Stokes equation for velocity and pressure.In the third step,we solve the Darcy equation for the piezometric head in the porous media domain.We use the numerical solutions at last time level to give the interface condition to decouple the Navier-Stokes equation and the Darcy’s equation.The stability analysis,under some condition △t≤k0,k0>0,is given.The error estimates prove our method has an optimal convergence rates.Finally,some numerical results are presented to show the performance of our algorithm.展开更多
In this paper, by combining the second order characteristics time discretization with the variational multiscale finite element method in space we get a second order modified characteristics variational multiscale fin...In this paper, by combining the second order characteristics time discretization with the variational multiscale finite element method in space we get a second order modified characteristics variational multiscale finite element method for the time dependent Navier- Stokes problem. The theoretical analysis shows that the proposed method has a good convergence property. To show the efficiency of the proposed finite element method, we first present some numerical results for analytical solution problems. We then give some numerical results for the lid-driven cavity flow with Re = 5000, 7500 and 10000. We present the numerical results as the time are sufficient long, so that the steady state numerical solutions can be obtained.展开更多
In this paper,a numerical method for the electroneutral micro-fluids based on thefinite element method will be given.In order to deal with the non-linearity of the equation,the modified characteristics method will be use...In this paper,a numerical method for the electroneutral micro-fluids based on thefinite element method will be given.In order to deal with the non-linearity of the equation,the modified characteristics method will be used to deal with the tempo-ral derivates term and the convective term.In this way,the non-linear equation can be linearlized.Then,we will give the unconditional stability and optimal error estima-tion.At last,some numerical results are given to show the effectiveness of our method.From the stability analysis we can see that the method is unconditionally stable.The numerical results show that our method is robust.展开更多
文摘In this report,we give a viscosity splitting method for the Navier-Stokes/Darcy problem.In this method,the Navier-Stokes/Darcy equation is solved in three steps.In the first step,an explicit/implicit formulation is used to solve the nonlinear problem.We introduce an artificial diffusion term qDu in our scheme whose purpose is to enlarge the time stepping and enhance numerical stability,especially for small viscosity parameter n,by choosing suitable parameter q.In the second step,we solve the Stokes equation for velocity and pressure.In the third step,we solve the Darcy equation for the piezometric head in the porous media domain.We use the numerical solutions at last time level to give the interface condition to decouple the Navier-Stokes equation and the Darcy’s equation.The stability analysis,under some condition △t≤k0,k0>0,is given.The error estimates prove our method has an optimal convergence rates.Finally,some numerical results are presented to show the performance of our algorithm.
文摘In this paper, by combining the second order characteristics time discretization with the variational multiscale finite element method in space we get a second order modified characteristics variational multiscale finite element method for the time dependent Navier- Stokes problem. The theoretical analysis shows that the proposed method has a good convergence property. To show the efficiency of the proposed finite element method, we first present some numerical results for analytical solution problems. We then give some numerical results for the lid-driven cavity flow with Re = 5000, 7500 and 10000. We present the numerical results as the time are sufficient long, so that the steady state numerical solutions can be obtained.
基金supported by the National Natural Science Foundation of China(No.11971152)the Fundamental Research Funds for the Universities of Henan Province(No.NSFRF180421)。
文摘In this paper,a numerical method for the electroneutral micro-fluids based on thefinite element method will be given.In order to deal with the non-linearity of the equation,the modified characteristics method will be used to deal with the tempo-ral derivates term and the convective term.In this way,the non-linear equation can be linearlized.Then,we will give the unconditional stability and optimal error estima-tion.At last,some numerical results are given to show the effectiveness of our method.From the stability analysis we can see that the method is unconditionally stable.The numerical results show that our method is robust.
