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以“粘性”机制为理论基础,近年来在壁面湍流高分子减阻研究中提出了一种拉伸的高分子会产生自洽的等效粘度模型,这种等效粘度随离开壁面的距离而改变。通过等效粘度模型与Navier-Stokes方程的结合,运用雷诺应力模型计算壁面湍流减阻,并与基于高分子有限拉伸的非线性弹性哑铃模型的直接数值模拟结果进行比较,进一步校验了此等效粘度理论。通过肋条破坏槽道流中的边界层,显示了边界层对高分子减阻的影响,结果表明只有形成稳定的边界层,高分子才能有减阻作用。边界层是高分子减阻的首要条件,边界层中的粘性底层和对数率分布区之间的缓冲层可能是减阻的主要影响区域。
Based on the theory of “viscous ” mechanism, in recent years in the wall turbulence polymer drag reduction study proposed a tensile polymer will produce self-consistent equivalent viscosity model, the equivalent viscosity with the wall Distance and change. Through the combination of the equivalent viscosity model and the Navier-Stokes equation, the Reynolds stress model is used to calculate the wall drag reduction, which is compared with the direct numerical simulation results of the nonlinear dumbbell model based on the finite stretching of polymers. Equivalent viscosity theory. The influence of the boundary layer on the drag reduction of the polymer is shown by the ribbing of the boundary layer in the channel flow. The result shows that the polymer can have a drag reduction effect only by forming a stable boundary layer. The boundary layer is the primary condition for polymer drag reduction. The buffer layer between the adhesive bottom and the logarithmic ratio distribution in the boundary layer may be the main influence area of drag reduction.