论文标题
部分可观测时空混沌系统的无模型预测
Yield-stress transition in suspensions of deformable droplets
论文作者
论文摘要
从理论上讲，屈服压力材料需要足够大的强迫流动。为了深入了解它们的屈服过渡，在这里，我们从数值上研究了在压力驱动流动下可变形液滴的悬浮液的流变。我们表明，悬浮液显示出屈服压力行为，当施加的身体强度低于临界值时，液滴保持一动不动。在非流动阶段，液滴果酱形成一个无定形结构，而它们在流动阶段中排序。屈服与液滴 - 滴头重叠的接触中的渗滤过渡有关，并且需要合适的润湿边界条件和严格的液滴区域的保护。接近屈服的过渡，我们发现液滴运动中的强振荡与在流动下的密闭胶体玻璃中实验发现的振荡非常相似。我们表明，即使液滴是静态的，基本的溶剂通过渗透来移动，因此复合系统的粘度永远不会是真正的无限，并且正如我们所讨论的那样，其精确的价值不再是系统的批量材料。
Yield-stress materials, which require a sufficiently large forcing to flow, are currently ill-understood theoretically. To gain insight into their yielding transition, here we study numerically the rheology of a suspension of deformable droplets under pressure-driven flow. We show that the suspension displays yield-stress behaviour, with the droplets remaining motionless when the applied body-force is below a critical value. In the non-flowing phase, droplets jam to form an amorphous structure, whereas they order in the flowing phase. Yielding is linked to a percolation transition in the contacts of droplet-droplet overlaps, and requires suitable wetting boundary conditions and strict conservation of the droplet area to exist. Close to the yielding transition, we find strong oscillations in the droplet motion which closely resemble those found experimentally in confined colloidal glasses under flow. We show that even when droplets are static the underlying solvent moves by permeation, so that the viscosity of the composite system is never truly infinite, and, as we discuss, its precise value ceases to be a bulk material property of the system.
