论文标题
聚合物在粘弹性剪切流中的运输和翻滚
Transport and tumbling of polymers in viscoelastic shear flow
论文作者
论文摘要
剪切流中的聚合物无处不在，我们在剪切下的粘弹性液中研究它们的运动。使用哑铃作为代表性，我们发现质量运动的中心以下：$ \ langle x^2_c（t）\ rangle \ sim \ sim \dotγ^2 t^{α+2}，〜0 <α<1 $，概括较早的结果：$ \ langle x^2_c（t）另一方面，相对坐标的运动非常有趣，因为小$α$的$ \ langle x^2_r（t）\ rangle \ sim t^β$ at $β= 2（1-α）$。这意味着稳态不存在。我们通过引入具有Fene-LJ相互作用的非线性弹簧并研究哑铃的倒闭动力学来解决这种病理。粘弹性的总体效果是减慢魏森伯格数量的实验观察到的范围中的动力学。我们从数值上获得了翻滚的特征时间，并表明$α$的小变化会导致大幅变化。
Polymers in shear flow are ubiquitous and we study their motion in a viscoelastic fluid under shear. Employing dumbbells as representative, we find that the center of mass motion follows: $\langle x^2_c(t) \rangle \sim \dotγ^2 t^{α+2}, ~0< α<1$, generalizing the earlier result: $\langle x^2_c(t) \rangle \sim \dotγ^2t^3 ~(α= 1)$. Motion of the relative coordinate, on the other hand, is quite intriguing in that $\langle x^2_r(t) \rangle \sim t^β$ with $β= 2(1-α)$ for small $α$. This implies nonexistence of the steady state. We remedy this pathology by introducing a nonlinear spring with FENE-LJ interaction and study tumbling dynamics of the dumbbell. The overall effect of viscoelasticity is to slow down the dynamics in the experimentally observed ranges of the Weissenberg number. We numerically obtain the characteristic time of tumbling and show that small changes in $α$ result in large changes in tumbling times.
