光滑和粗糙明槽湍流流动结构分析

采用大涡模拟方法和Ｓｍａｇｏｒｉｎｓｋｙ及Ｄｙｎａｍｉｃ亚格子（ＳＧＳ）模拟数值计算了光滑及粗糙明槽湍流运动。以槽高为参考长度和来流平均流速为参考速度的雷诺数分别为３０００、２２８００和１０＾５，数值离散方法为有限体积法，自由面处理使用了简单的刚盖假定，固壁面采用了壁函数。与低雷诺数直接模拟和物理实验结果相比，本文数模呈现了良好的预测结果，也揭示了自由面附近不同于固壁的湍流结构。

Structure analysis of turbulent flows of smooth and rough open|channels

Turbulent flows of smooth and rough open|channels are predicted by Large Eddy Simulation(LES) combined with Smagorinsky and dynamical SGS models. The Reynolds numbers are 3 000, 22 800 and 10 5 respectively based on the bulk velocity ( u b ) of flows and depth ( h ) of the channel. The three|dimensional Finite Volume Method is used to discretize the computational domain, the rigid|lid assumption to cope with the free surface and wall function to the solid wall. Compared with Direct Numerical Simulation (DNS) and experimental data, good results are achieved for most of mean and fluctuation quantities of turbulence. By the hydrogen|bubble technology, different structures of turbulence near the solid wall and free surface are displayed also.