Saintyves Baudouin, Rallabandi Bhargav, Jules Theo, Ault Jesse, Salez Thomas, Schönecker Clarissa, Stone Howard A, Mahadevan L
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Department of Mechanical Engineering, University of California, Riverside, California 92521, USA.
Soft Matter. 2020 Apr 29;16(16):4000-4007. doi: 10.1039/c9sm02344e.
A submerged finite cylinder moving under its own weight along a soft incline lifts off and slides at a steady velocity while also spinning. Here, we experimentally quantify the steady spinning of the cylinder and show theoretically that it is due to a combination of an elastohydrodynamic torque generated by flow in the variable gap, and the viscous friction on the edges of the finite-length cylinder. The relative influence of the latter depends on the aspect ratio of the cylinder, the angle of the incline, and the deformability of the substrate, which we express in terms of a single scaled compliance parameter. By independently varying these quantities, we show that our experimental results are consistent with a transition from an edge-effect dominated regime for short cylinders to a gap-dominated elastohydrodynamic regime when the cylinder is very long.
一个在自身重力作用下沿软质斜坡移动的水下有限长圆柱体，会在旋转的同时抬起并以稳定速度滑动。在此，我们通过实验对圆柱体的稳定旋转进行了量化，并从理论上表明，这是由可变间隙中流体产生的弹性流体动力扭矩与有限长圆柱体边缘的粘性摩擦共同作用的结果。后者的相对影响取决于圆柱体的纵横比、斜坡角度以及基底的可变形性，我们用一个单一的标度柔度参数来表示这些因素。通过独立改变这些量，我们表明实验结果与从短圆柱体的边缘效应主导状态到长圆柱体的间隙主导弹性流体动力状态的转变是一致的。
