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arXiv · 2506.09692

Deformation of ellipsoidal droplets in homogeneous and isotropic turbulence

Fabio Guglietta·Diego Taglienti·Mauro Sbragaglia
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Abstract

We study the statistics of deformation of neutrally buoyant droplets in homogeneous isotropic turbulence (HIT), wherein the characteristic droplet size $R$ is smaller than the characteristic Kolmogorov scale $\eta$ of the turbulent flow. We systematically focus on the characterization of droplet statistics obtained with various phenomenological ellipsoidal models (EMs) -- assuming that the droplet preserves the ellipsoidal shape at all times - with the droplet moving as a passive tracer in the turbulent flow. The predictions of the EMs are compared with ground-truth data obtained with three-dimensional fully resolved simulations (FRSs) without any ad-hoc assumption on the droplet shape. Our work helps in elucidating the applicability of the EMs in describing droplet deformation in HIT at changing the capillary number $\text{Ca}=\tau_{\sigma}/\tau_{\eta}$, weighting the relative importance of the droplet characteristic time $\tau_{\sigma}$ with respect to the turbulent flow characteristic time $\tau_{\eta}$.

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Fabio Guglietta, Diego Taglienti, Mauro Sbragaglia. 2025-06-11. Deformation of ellipsoidal droplets in homogeneous and isotropic turbulence. https://arxiv.org/abs/2506.09692

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