标题： 粘弹性灾变 显示英文标题

标题： A Viscoelastic Catastrophe

摘要： 我们使用一个微分本构方程来模拟在交叉槽几何结构中粘弹性流体的流动，该结构在临界流速以上已知表现出双稳态特性。 新颖之处在于对几何结构的两个不对称修改，这导致分岔图发生变化，使得其中一个稳定解与低流速下的解断开。 首先，我们证明可以通过镜像其中一个修改，使系统被强制到断开的解。 然后，我们表明流速的缓慢降低可以在短时间内引起系统的剧烈变化，这也被称为突变。 短时间尺度可能导致精确且简单的实验测量粘弹性突变发生的流动条件。 由于这一现象本质上与流体的拉伸流变学相关，我们建议利用这一现象进行在线拉伸流变测量。 显示英文摘要

摘要： We use a differential constitutive equation to model the flow of a viscoelastic flow in a cross-slot geometry, which is known to exhibit bistability above a critical flow rate. The novelty lies in two asymmetric modifications to the geometry, which causes a change in the bifurcation diagram such that one of the stable solutions becomes disconnected from the solution at low flow speeds. First we show that it is possible to mirror one of the modifications such that the system can be forced to the disconnected solution. Then we show that a slow decrease of the flow rate, can cause the system to go through a drastic change on a short time scale, also known as a catastrophe. The short time scale could lead to a precise and simple experimental measurement of the flow conditions at which the viscoelastic catastrophe occurs. Since the phenomena is intrinsically related to the extensional rheology of the fluid, we propose to exploit the phenomena for in-line extensional rheometry.