中文摘要：

近来在壁面湍流高分子减阻研究中,一种拉伸的高分子产生自相一致的等效粘度的理论提了出来,这个等效粘度随离开壁面的距离而增长。本文将此线性分布等效粘度置入Navier-Stokes方程,运用雷诺应力模型计算在壁面湍流中的减阻情况,检验这种等效粘度的可行性。可以发现,此模型可以得到湍流减阻的效果,所得到的减阻率随着等效粘度线性分布斜率的增加增大到一个饱和值。本文得到了接近最大减阻极限的减阻率（75%）。且由此模型计算得到的减阻湍流特征值包括平均速度分布、速度脉动均方根、雷诺应力及粘性应力分布都与实验数据和直接数值模拟结果相符。该线性分布等效粘度减阻模型大致上把握了高分子湍流减阻特性,给出了在一定程度上对湍流减阻机理普适和合理的解释。

英文摘要：

In recent studies of drag reduction in wall turbulence it was proposed that the streching polymer produces a self-consistent effective viscosity that increases with the distance from the wall.This linear effective viscosity theory for drag reduction in the wall-bounded turbulent flow was examined by introducing such linear viscosity profile to Navier-Stokes equation,and computing with Reynolds stress model.It shows that the linear effective viscosity model demonstrates drag reducing properties,and the percentage of the drag reduction increases up to the drag reduction saturation with the slope of viscosity profile increasing.The level of drag reduction up to about 75%,approaching the maximum drag reduction extent was obtained.The turbulence important characteristics including mean velocity profile,root-mean-square velocity fluctuations,Reynolds stress and viscous stress profiles are in agreement with the direct numerical simulation results and experimental data.It is universal and reasonable in some content for the linear viscosity profile model to explain drag reduction mechanism.