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Updated: Apr 21, 2026

The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
Elliptical tracers in two-dimensional, homogeneous, isotropic fluid turbulence: the statistics of alignment,
Anupam Gupta1, Dario Vincenzi2, Rahul Pandit1
1Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
Abstract:
We study the statistical properties of orientation and rotation dynamics of elliptical tracer particles in two-dimensional, homogeneous, and isotropic turbulence by direct numerical simulations. We consider both the cases in which the turbulent flow is generated by forcing at large and intermediate length scales. We show that the two cases are qualitatively different. For large-scale forcing, the spatial distribution of particle orientations forms large-scale structures, which are absent for intermediate-scale forcing. The alignment with the local directions of the flow is much weaker in the latter case than in the former. For intermediate-scale forcing, the statistics of rotation rates depends weakly on the Reynolds number and on the aspect ratio of particles. In contrast with what is observed in three-dimensional turbulence, in two dimensions the mean-square rotation rate increases as the aspect ratio increases.
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