A method to develop unified artificial boundaries for problems coupling static effect and dynamic effect is proposed. Based on the dynamic viscous-spring artificial boundary and the fundamental solution of static prob...A method to develop unified artificial boundaries for problems coupling static effect and dynamic effect is proposed. Based on the dynamic viscous-spring artificial boundary and the fundamental solution of static problems in elastic half space, a unified viscous-spring artificial boundary for 3-D static and dynamic applications is established.展开更多
A new method for direct numerical simulation of incompressible Navier-Stokes equations is studied in the paper. The compact finite difference and the non-linear terms upwind compact finite difference schemes on non-un...A new method for direct numerical simulation of incompressible Navier-Stokes equations is studied in the paper. The compact finite difference and the non-linear terms upwind compact finite difference schemes on non-uniform meshes in x and y directions are developed respectively. With the Fourier spectral expansion in the spanwise direction, three-dimensional N-S equation are converted to a system of two-dimensional explicit-implicit The treatment of equations. The third-order mixed scheme is employed the three-dimensional for time integration. non-reflecting outflow boundary conditions is presented, which is important for the numerical simulations of the problem of transition in boundary layers, jets, and mixing layer. The numerical results indicate that high accuracy, stabilization and efficiency are achieved by the proposed numerical method. In addition, a theory model for the coherent structure in a laminar boundary layer is also proposed, based on which the numerical method is implemented to the non-linear evolution of coherent structure. It is found that the numerical results of the distribution of Reynolds stress, the formation of high shear layer, and the event of ejection and sweeping, match well with the observed characteristics of the coherent structures in a turbulence boundary layer.展开更多
基金This work was supported by the Special Funds for the Major State Basic Research Project(Grant No.2002CB4 12706)the National Natural Science Foundation of China(Grant No.50478014).
文摘A method to develop unified artificial boundaries for problems coupling static effect and dynamic effect is proposed. Based on the dynamic viscous-spring artificial boundary and the fundamental solution of static problems in elastic half space, a unified viscous-spring artificial boundary for 3-D static and dynamic applications is established.
基金Project supported by the National Natural Science Foundation of China (Grant No:10272040) and Doctor Foundation of Education Ministry (Grant No:20050294003)
文摘A new method for direct numerical simulation of incompressible Navier-Stokes equations is studied in the paper. The compact finite difference and the non-linear terms upwind compact finite difference schemes on non-uniform meshes in x and y directions are developed respectively. With the Fourier spectral expansion in the spanwise direction, three-dimensional N-S equation are converted to a system of two-dimensional explicit-implicit The treatment of equations. The third-order mixed scheme is employed the three-dimensional for time integration. non-reflecting outflow boundary conditions is presented, which is important for the numerical simulations of the problem of transition in boundary layers, jets, and mixing layer. The numerical results indicate that high accuracy, stabilization and efficiency are achieved by the proposed numerical method. In addition, a theory model for the coherent structure in a laminar boundary layer is also proposed, based on which the numerical method is implemented to the non-linear evolution of coherent structure. It is found that the numerical results of the distribution of Reynolds stress, the formation of high shear layer, and the event of ejection and sweeping, match well with the observed characteristics of the coherent structures in a turbulence boundary layer.
