Flutter to tumble transition of buoyant spheres triggered by rotational inertia changes.

ABSTRACT: Heavy particles sink straight in water, while buoyant bubbles and spheres may zigzag or spiral as they rise. The precise conditions that trigger such path-instabilities are still not completely understood. For a buoyant rising sphere, two parameters are believed to govern the development of unsteady dynamics: the particle's density relative to the fluid, and its Galileo number. Consequently, with these parameters specified, the opportunities for variation in particle dynamics appear limited. In contrast to this picture, here we demonstrate that vigorous path-oscillations can be triggered by modulating a spherical particle's moment of inertia (MoI). For a buoyant sphere rising in a turbulent flow, MoI reduction triggers a tumble-flutter transition, while in quiescent liquid, it induces a mo

SUBMITTER: Mathai V 

PROVIDER: S-EPMC5935758 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature