Abstract Fall of open tori horizontally dropped in quiescent water is experimentally investigated. The fall is controlled by the Galileo number, the torus aspect ratio and the solid to fluid density ratio. The dependence of the descent velocity and of the drag coefficient on the control parameters is first analyzed. As the control parameters are varied, vertical translation, zigzagging and spiraling descent are observed. These different descent modes are characterized and a phase diagram of the falling tori are presented as function of the three control parameters.

中文翻译：

---

开放式花托坠落实验

摘要 对水平落入静止水中的开放式环面的坠落进行了实验研究。下降由伽利略数、环面纵横比和固液密度比控制。首先分析下降速度和阻力系数对控制参数的依赖性。随着控制参数的变化，观察到垂直平移、曲折和螺旋下降。这些不同的下降模式被表征，并且下降环的相位图被呈现为三个控制参数的函数。