A theoretical model for identica l coherent structures in the wall region of a turbulent boundary layer was propo sed, using the idea of general resonant triad of the hydrodynamic stability. The evolution of the stru...A theoretical model for identica l coherent structures in the wall region of a turbulent boundary layer was propo sed, using the idea of general resonant triad of the hydrodynamic stability. The evolution of the structures in the wall region of a turbulent boundary layer wa s studied by combining the compact finite differences of high numerical accuracy and the Fourier spectral hybrid method for solving the three dimensional Navier -Stokes equations. In this method, the third order mixed explicit-implicit sch eme was applied for the time integration. The fifth-order upwind compact finite difference schemes for the nonlinear convection terms in the physical space, an d the sixth-order center compact schemes for the derivatives in spectral space were introduced, respectively. The fourth-order compact schemes satisfied by th e velocities and pressure in spectral space was derived. As an application, the method was implemented to the wall region of a turbulent boundary to study the e volution of identical coherent structures. It is found that the numerical result s are satisfactory.展开更多
文摘A theoretical model for identica l coherent structures in the wall region of a turbulent boundary layer was propo sed, using the idea of general resonant triad of the hydrodynamic stability. The evolution of the structures in the wall region of a turbulent boundary layer wa s studied by combining the compact finite differences of high numerical accuracy and the Fourier spectral hybrid method for solving the three dimensional Navier -Stokes equations. In this method, the third order mixed explicit-implicit sch eme was applied for the time integration. The fifth-order upwind compact finite difference schemes for the nonlinear convection terms in the physical space, an d the sixth-order center compact schemes for the derivatives in spectral space were introduced, respectively. The fourth-order compact schemes satisfied by th e velocities and pressure in spectral space was derived. As an application, the method was implemented to the wall region of a turbulent boundary to study the e volution of identical coherent structures. It is found that the numerical result s are satisfactory.
