## Title data

Pujara, Nimish ; Arguedas-Leiva, José-Agustín ; Lalescu, Cristian ; Bramas, Bérenger ; Wilczek, Michael:

**Shape- and scale-dependent coupling between spheroids and velocity gradients in turbulence.**

*In:* Journal of Fluid Mechanics.
Vol. 922
(2021)
.
- R6.

ISSN 0022-1120

DOI: https://doi.org/10.1017/jfm.2021.543

## Abstract in another language

Rotations of spheroidal particles immersed in turbulent flows reflect the combined effects of fluid strain and vorticity, as well as the time history of these quantities along the particle’s trajectory. Conversely, particle rotation statistics in turbulence provide a way to characterise the Lagrangian properties of velocity gradients. Particle rotations are also important for a range of environmental and industrial processes where particles of various shapes and sizes are immersed in a turbulent flow. In this study, we investigate the rotations of inertialess spheroidal particles that follow Lagrangian fluid trajectories. We perform direct numerical simulations (DNS) of homogeneous isotropic turbulence and investigate the dynamics of different particle shapes at different scales in turbulence using a filtering approach.We find that the mean-square particle angular velocity is nearly independent of particle shape across all scales from the Kolmogorov scale to the integral scale. The particle shape does determine the relative split between different modes of rotation (spinning vs tumbling), but this split is also almost independent of the filter scale suggesting a Lagrangian scale-invariance in velocity gradients. We show how the split between spinning and tumbling can be quantitatively related to the particle’s alignment with respect to the fluid vorticity.

## Further data

Item Type: | Article in a journal |
---|---|

Refereed: | Yes |

Institutions of the University: | Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Theoretical Physics I > Chair Theoretical Physics I - Univ.-Prof. Dr. Michael Wilczek Profile Fields > Advanced Fields > Nonlinear Dynamics Faculties Faculties > Faculty of Mathematics, Physics und Computer Science Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Theoretical Physics I Profile Fields Profile Fields > Advanced Fields |

Result of work at the UBT: | No |

DDC Subjects: | 500 Science > 530 Physics |

Date Deposited: | 24 Feb 2022 11:23 |

Last Modified: | 05 Jul 2022 09:40 |

URI: | https://eref.uni-bayreuth.de/id/eprint/67621 |