论文标题
粘弹性悬浮
Viscoelastic levitation
论文作者
论文摘要
粘弹性的影响已显示出通过对称性破坏来表现出来。在这项调查中，我们展示了从这个想法引起的一种新颖现象。我们观察到，当一个密集的球旋转在墙壁附近（旋转与壁正常方向和重力对齐）时，它会悬浮至距墙壁的固定距离。由于间隙（在球体和壁之间）中的剪切比在球体的开放侧大，因此剪切诱导的弹性应力是不对称的，导致净弹性垂直力平衡球的重量。我们进行实验，理论模型和数值模拟，以在Boger型流体中进行各种大小和密度的旋转球体。在少量的黛博拉数范围内，通过考虑弹性与重力的比例的无量纲组，将结果折叠成普遍的趋势。
The effects of viscoelasticity have been shown to manifest themselves via symmetry breaking. In this investigation, we show a novel phenomenon that arises from this idea. We observe that when a dense sphere is rotated near a wall (the rotation being aligned with the wall-normal direction and gravity), it levitates to a fixed distance away from the wall. Since the shear is larger in the gap (between the sphere and the wall) than in the open side of the sphere, the shear-induced elastic stresses are thus asymmetric, resulting in a net elastic vertical force that balances the weight of the sphere. We conduct experiments, theoretic models, and numerical simulations for rotating spheres of various sizes and densities in a Boger-type fluid. In the small Deborah number range, the results are collapsed into a universal trend by considering a dimensionless group of the ratio of elastic to gravitational forces.
