Dey Subhasish, Zeeshan Ali Sk, Padhi Ellora
Department of Civil Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India.
Physics and Applied Mathematics Unit, Indian Statistical Institute, Kolkata, West Bengal 700108, India.
Proc Math Phys Eng Sci. 2019 Aug;475(2228):20190277. doi: 10.1098/rspa.2019.0277. Epub 2019 Aug 28.
This review article, dedicated to the bicentenary celebration of Sir George Gabriel Stokes' birthday, presents the state-of-the-science of terminal fall velocity, highlighting his rich legacy from the perspective of fluvial hydraulics. It summarizes the fluid drag on a particle and the current status of the drag coefficient from both the theoretical and empirical formulations, highlighting the three major realms-Stokesian, transitional and Newtonian realms. The force system that drives the particle motion falling through a fluid is described. The response of terminal fall velocity to key factors, which include particle shape, hindered settling and turbulence (nonlinear drag, vortex trapping, fast tracking and effects of loitering), is delineated. The article puts into focus the impact of terminal fall velocity on fluvial hydraulics, discussing the salient role that the terminal fall velocity plays in governing the hydrodynamics of the sediment threshold, bedload transport and suspended load transport. Finally, an innovative perspective is presented on the subject's future research track, emphasizing open questions.
这篇综述文章是为庆祝乔治·加布里埃尔·斯托克斯爵士诞辰两百周年而作，介绍了终端沉降速度的科学现状，从河流动力学的角度突出了他丰富的遗产。文章总结了颗粒上的流体阻力以及理论和经验公式中阻力系数的现状，突出了三个主要领域——斯托克斯领域、过渡领域和牛顿领域。描述了驱动颗粒在流体中下落运动的力系。阐述了终端沉降速度对关键因素的响应，这些因素包括颗粒形状、受阻沉降和湍流（非线性阻力、涡旋捕获、快速跟踪和滞留效应）。文章重点关注终端沉降速度对河流动力学的影响，讨论了终端沉降速度在控制沉积物阈值、推移质输运和悬移质输运的水动力学方面所起的显著作用。最后，针对该主题的未来研究方向提出了创新观点，强调了开放性问题。
