The year 2019 marked the bicentenary of George Gabriel Stokes, who in 1851 described the drag—Stokes drag—on a body moving immersed in a fluid, and 2020 is the centenary of Christopher Robin Milne, for whom the game of poohsticks was invented; his father A. A. Milne’s The House at Pooh Corner, in which it was first described in print, appeared in 1928. So this is an apt moment to review the state of the art of the fluid mechanics of a solid body in a complex fluid flow, and one floating at the interface between two fluids in motion. Poohsticks pertains to the latter category, when the two fluids are water and air. This article is part of the theme issue ‘Stokes at 200 (part 2)’.

中文翻译：

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poohsticks 的流体力学

2019 年是乔治·加布里埃尔·斯托克斯 (George Gabriel Stokes) 诞辰 200 周年，他在 1851 年描述了浸没在液体中的身体上的阻力——斯托克斯阻力；而 2020 年是克里斯托弗·罗宾·米尔恩 (Christopher Robin Milne) 诞辰 100 周年，他发明了小熊棒游戏；他的父亲 AA Milne 的《维尼角的房子》（The House at Pooh Corner）于 1928 年首次出现在印刷版中。因此，这是回顾复杂流体流动中固体流体力学最先进技术的最佳时机，一种漂浮在两种运动流体的界面上。Poohsticks 属于后一类，当两种流体是水和空气时。本文是主题问题“斯托克斯 200（第 2 部分）”的一部分。