Open Conference Systems, DDAYS LAC 2024 Main Conference

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Effect of local flow geometry on particle pair dispersion angle
Bernardo Luciano Español

Building: Cero Infinito
Room: 1403
Date: 2024-12-13 03:20 PM – 03:40 PM
Last modified: 2024-11-25

Abstract


In a turbulent flow, particles are separated through a highly sensitive and chaotic process. Small differences in their initial conditions can lead to exponentially diverging trajectories, quantified by the Lyapunov exponent. This process leads to a supper-diffusive behavior, where the particles mix rapidly. Understanding this phenomenon offers insights into the underlying dynamics of this type of complex systems. In this work we combine experiments in a von Kármán flow with numerical simulations of Taylor-Green and homogeneous isotropic turbulence to investigate how local flow geometry impacts particle pair dispersion. To characterize particle dispersion we use the pair dispersion angle, defined as the angle between the particles relative position and their relative velocity. This angle provides a clearer distinction of various dispersion regimes in finite Reynolds number systems, in both experimental and numerical data. Globally all flows display similar dispersion properties, with ballistic, super-diffusive, and diffusive regimes. However, locally these flows result in distinct behavior, with anisotropies and the local flow geometry playing relevant roles in dispersion in von Kármán and Taylor-Green flows.