Polymer dynamics in a model of the turbulent buffer layer
Polymer dynamics in a model of the turbulent buffer layer
复制标题
湍流缓冲层模型中的聚合物动力学
DOI：
10.1063/1.1563258
复制
发表时间：
2003
影响因子：
4.6
通讯作者：
M. Graham
中科院分区：
文献类型：
--
作者：
P. A. Stone;M. Graham
珠弹簧链聚合物动力学的布朗动力学研究是在一个模型流中进行的，该模型流捕获了叠加在平均剪切上的近壁湍流波状流向涡的缓冲区的关键特征。在这个流和任何拉格朗日混沌流中，胡克哑铃聚合物将无限拉伸，当且仅当基于速度场的最大李雅普诺夫指数的Weissenberg数是12。在这里调查的流中，这个标准被发现是很好的预测时，可伸缩链的拉伸接近其最大值。链在流向条纹中变得高度拉伸，并随着它们移动到涡核内和周围而松弛，从而导致流动的不同区域中的应力的巨大差异。聚合物链段之间的流体动力学和排除体积相互作用没有定性的影响，一旦结果被归一化的弛豫时间的变化，由于它们的列入。从珠弹簧链模型的结果被用来…
A Brownian dynamics study of bead–spring–chain polymer dynamics is undertaken in a model flow that captures key features of the buffer region of near-wall turbulence—wavy streamwise vortices superimposed on a mean shear. In this flow and in any Lagrangian chaotic flow, a Hookean dumbbell polymer will stretch indefinitely if and only if the Weissenberg number based on the largest Lyapunov exponent for the velocity field is ⩾12. In the flow investigated here, this criterion is found to be good predictor of when the stretch of finitely extensible chains approaches its maximum value. The chains become highly stretched in the streamwise streaks and relax as they move into and around the vortex cores, leading to large differences in stress in different regions of the flow. Hydrodynamic and excluded volume interactions between polymer segments have no qualitative effects once results are normalized for the change in relaxation time due to their inclusion. The results from the bead–spring–chain models are used to...