Wall effects on a sphere translating at constant velocity
Wall effects on a sphere translating at constant velocity
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匀速平移球体上的壁效应
DOI：
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发表时间：
1984
影响因子：
3.7
通讯作者：
E. Guyon
中科院分区：
文献类型：
--
作者：
By A. Ambarit;B. Gauthier;E. Guyon
本文给出了磁悬浮中位置由光反馈系统保持不变的球体所受的修正斯托克斯力F的实验结果。牛顿液体相对于球体以恒定速度U运动。我们在两种不同的情况下考虑这项动议。(I)当球体接近垂直于U的壁面时，由于润滑引起的|F|的增加与Brenner(1961)和Maude(1961)等人的理论结果定量一致，这些结果忽略了流场的不稳定性。(Ii)在球体沿圆柱管轴线运动的互补情况下，我们的结果表示为轨迹偏心率和两个半径之比的函数，证实和推广了以前的理论分析。它们特别说明了离开圆柱体轴线的最小|F|的存在，以及当球体接近侧壁时|F|的急剧增加。通过与球体平行于平壁运动的结果进行比较，分析了圆柱管的曲率对计算结果的影响。
We present experimental results on the modified Stokes force F exerted on a sphere in magnetic levitation whose position is kept fixed by an optical feedback system. A Newtonian liquid moves at a constant velocity U relative to the sphere. We consider the motion in two different situations. (i) When the sphere approaches a wall perpendicular to U, the increase in |F| due to lubrication agrees quantitatively with theoretical results such as those of Brenner (1961) and Maude (1961), obtained neglecting the unsteadiness of the flow field. (ii) In the complementary situation of a sphere moving along the axis of a cylindrical tube, our results expressed as a function of the eccentricity of the trajectory and of the ratio of the two radii confirm and extend previous theoretical analyses. They show in particular the existence of a minimum of |F| away from the axis of the cylinder and a sharp increase in |F| when the sphere approaches the sidewall. By comparing with the results for a sphere moving parallel to a flat wall, we analyse the effect of the curvature of the cylindrical tube.