Hydrodynamic interactions and extreme particle clustering in turbulence

Journal Article (Journal Article)

Expanding recent observations by Hammond & Meng (J. Fluid Mech., vol. 921, 2021, A16), we present a range of detailed experimental data of the radial distribution function (r.d.f.) of inertial particles in isotropic turbulence for different Stokes number, showing that the r.d.f. grows explosively with decreasing separation r, exhibiting scaling as the collision radius is approached, regardless of or particle radius. To understand such explosive clustering, we correct a number of errors in the theory by Yavuz et al. (Phys. Rev. Lett., vol. 120, 2018, 244504) based on hydrodynamic interactions between pairs of small, weakly inertial particles. A comparison between the corrected theory and the experiment shows that the theory by Yavuz et al. underpredicts the r.d.f. by orders of magnitude. To explain this discrepancy, we explore several alternative mechanisms for this discrepancy that were not included in the theory and show that none of them are likely the explanation. This suggests new, yet-to-be-identified physical mechanisms are at play, requiring further investigation and new theories.

Full Text

Duke Authors

Cited Authors

  • Bragg, AD; Hammond, AL; Dhariwal, R; Meng, H

Published Date

  • February 25, 2022

Published In

Volume / Issue

  • 933 /

Electronic International Standard Serial Number (EISSN)

  • 1469-7645

International Standard Serial Number (ISSN)

  • 0022-1120

Digital Object Identifier (DOI)

  • 10.1017/jfm.2021.1099

Citation Source

  • Scopus