The motion of a cylinder of fluid released from rest in a cross-flow
The motion of a cylinder of fluid released from rest in a cross-flow
复制标题
流体圆柱体以横流方式从静止状态释放出来的运动
DOI：
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发表时间：
1987
影响因子：
3.7
通讯作者：
P. Stansby
中科院分区：
文献类型：
--
作者：
J. Rottman;J. Simpson;P. Stansby
本文研究了流体圆柱体从静止状态释放到均匀流中的二维运动。我们考虑的情况下，圆柱体最初是圆形横截面和流体是无粘或粘性。对于无粘流体，我们使用解析方法来确定释放后的小时间和大时间的运动，并使用三种数值方法，涡面方法，涡滴方法和涡胞方法来确定中间时间的运动。对于粘性流体的问题，我们使用的涡在细胞的方法与随机游动计算的初始流动的圆柱体周围的释放流体的运动在雷诺数为484。在无粘性的情况下，释放的流体变形成类似于以小于起始流速的速度向下游传播的涡对的结构。在粘性情况下，在代表卡门涡街的尾流形成后，释放的流体通常变形为细长的马蹄形，以大于或小于入射流速的速度向下游行进（取决于圆柱体在旋涡脱落循环中何时被释放）。数值计算的结果与一些简单的水槽实验进行了比较。
The two-dimensional motion of a cylinder of fluid released from rest into a flow that is uniform far upstream of the cylinder is studied. We consider cases where the cylinder is initially of circular cross-section and the fluid is either inviscid or viscous. For the inviscid fluid, we use analytical methods to determine the motion for small and large times after release and three numerical methods, the vortex-sheet method, the vortex-blob method and the vortex-in-cell method, to determine the intermediate-time motion. For the viscous-fluid problem we use the vortex-in-cell method with random walks to compute both the initial flow around the cylinder and the motion of the released fluid at a Reynolds number of 484. In the inviscid case, the released fluid deforms into a structure that resembles a vortex pair that propagates down stream at a speed less than the onset flow speed. In the viscous case, after a wake representative of a Kármán vortex street has developed, the released fluid usually deforms into an elongated horseshoe shape that travels downstream at a speed greater or less than the incident flow speed (depending on when in the vortex-shedding cycle the cylinder is released). The results of the numerical calculations are compared with some simple experiments in a water channel.