重点实验室学术报告会 6.10 (报告人： 陈十一教授）
发布时间: 2011-06-30 12:49:00
报告题目： 约束变分与多尺度流体力学 (Constrained Variation and Multiscale Fluid Mechanics)
报告人： 陈十一教授
时间： 2011年6月10日11:30
地点： 力学楼434会议室
时间： 2011年6月10日11:30
地点： 力学楼434会议室
Finding physically consistent solutions in multiscale methods is crucial for various modeling and simulations of fluid mechanics. A framework for continuum and molecular dynamics hybrid multiscale method has been recently developed to simulate micro- and nano-fluid flows. In this approach, the continuum Navier-Stokes equation is used in one flow region and atomistic molecular dynamics in another. The spatial coupling between two methods is achieved through the constrained variation in an overlap region. The hybrid methods are verified and used to study various problems, including the
singularity problems in the driven cavity and moving contact lines.
The similar idea of constrained variation has also been used for developing constrained dynamic subgrid-scale (C-SGS) stress model of fluid turbulence and Reynolds Stress Constrained Multiscale Large Eddy Simulation (RSC-LES) for wall-bounded turbulence with massive separation. In the C-SGS, we impose physical constraints in the dynamic procedure of calculating the SGS coefficients. The comparison between the large eddy simulation results in steady and decay isotropic turbulence using constrained and non-constrained SGS models and those from direct numerical simulation (DNS) will be presented.For RSC-LES, our model is able to predict mean velocity, turbulent stress and skin friction coefficients more accurately in turbulent channel flow and to estimate the pressure coefficient after separation more precisely in flow past a circular cylinder and flow over periodic hills compared with pure dynamic Smagorinsky model (DSM) and detached eddy simulation (DES) using the same grid resolution.
singularity problems in the driven cavity and moving contact lines.
The similar idea of constrained variation has also been used for developing constrained dynamic subgrid-scale (C-SGS) stress model of fluid turbulence and Reynolds Stress Constrained Multiscale Large Eddy Simulation (RSC-LES) for wall-bounded turbulence with massive separation. In the C-SGS, we impose physical constraints in the dynamic procedure of calculating the SGS coefficients. The comparison between the large eddy simulation results in steady and decay isotropic turbulence using constrained and non-constrained SGS models and those from direct numerical simulation (DNS) will be presented.For RSC-LES, our model is able to predict mean velocity, turbulent stress and skin friction coefficients more accurately in turbulent channel flow and to estimate the pressure coefficient after separation more precisely in flow past a circular cylinder and flow over periodic hills compared with pure dynamic Smagorinsky model (DSM) and detached eddy simulation (DES) using the same grid resolution.