壁面在展向作周期运动的槽道湍流的大涡模拟

分别采用3种亚格子模式:传统的Smagorinsky模式、动力Smagorinsky模式和Cui(2004)基于Kolmogorov方程所提出的新模式,对壁面在展向作周期运动的槽道湍流进行了大涡模拟,以考察这3种模式对平均运动为三维、非定常的湍流流动的模拟能力.通过对湍流基本统计量的分析,发现动力模式和新模式都可以较好地预测这种三维非定常的湍流流动;对相位平均的湍流统计量,动力模式的结果略优于新模式;传统的Smagorinsky模式对这种流动的预测结果是最差的.

Large Eddy Simulation of Turbulent Channel Flows with an Oscillating Wall in Spanwise Direction

Large eddy simulations with three subgrid eddy viscosity models,i.e., the classic Smagorinsky model,the dynamical Smagorinsky model and a model derived from Kolmogorov equation by Cui(2004),are performed to study turbulent channel flows with a wall oscillation in the spanwise direction.The capability of the subgrid eddy viscosity models in predicting statistical three-dimensional unsteady flows is evaluated.It is found that the new model and the dynamical model are both capable of predicting three-dimensional unsteady turbulent flows;and the dynamical model can achieve a higher accuracy;the classic Smagorinsky model yields the worst result.