article published yes Annalisa De Leo author Stefano Brizzolara author 4bbe33b8-c59a-11ee-a1af-fa33d1ac42c4 Mattia Cavaiola author Junlin He author Alessandro Stocchino author BjHo department IST-BRIDGE: International postdoctoral program project From anthropogenic litter carried by ocean currents to plant stems travelling through the atmosphere, geophysical flows are often seeded with elongated, fibre-like particles. In this study, we used a large-scale laboratory model of a tidal current – representative of a widespread class of geophysical flows – to investigate the tumbling motion of long, slender and floating fibres in the complex turbulence generated by flow interactions with a tidal inlet. Despite the non-stationary, non-homogeneous and anisotropic nature of this turbulence, we find that long fibres statistically rotate at the same frequency as eddies of similar size, a phenomenon called scale selection, which is known to occur in ideal turbulence. Furthermore, we report that the signal of the instantaneous transverse velocity difference between the fibre ends changes significantly from the signal produced by the flow in the fibre surroundings, although the two are statistically equivalent. These observations have twofold implications. On the one hand, they confirm the reliability of using the end-to-end velocity signal of rigid fibres to probe the two-point transverse statistics of the flow, even under realistic conditions: oceanographers could exploit this observation to measure transverse velocity differences through elongated floats in the field, where superdiffusion complicates collecting sufficient data to probe two-point turbulence statistics at a fixed separation effectively. On the other hand, by addressing the dynamics of inertial range particles floating in the coastal zone, these observations are crucial to improving our ability to predict the fate of meso- and macro-litter, a size class that is currently understudied. https://research-explorer.ista.ac.at/download/19729/19751/2025_JourFluidMech_DeLeo.pdf application/pdfno Cambridge University Press2025 eng 0022-1120 1469-7645 00148915970000110.1017/jfm.2025.362 1011 De Leo, A., Brizzolara, S., Cavaiola, M., He, J., &#38; Stocchino, A. (2025). Rigid fibre transport in a periodic non-homogeneous geophysical turbulent flow. <i>Journal of Fluid Mechanics</i>. Cambridge University Press. <a href="https://doi.org/10.1017/jfm.2025.362">https://doi.org/10.1017/jfm.2025.362</a> A. De Leo, S. Brizzolara, M. Cavaiola, J. He, and A. Stocchino, “Rigid fibre transport in a periodic non-homogeneous geophysical turbulent flow,” <i>Journal of Fluid Mechanics</i>, vol. 1011. Cambridge University Press, 2025. De Leo, Annalisa, et al. “Rigid Fibre Transport in a Periodic Non-Homogeneous Geophysical Turbulent Flow.” <i>Journal of Fluid Mechanics</i>, vol. 1011, A5, Cambridge University Press, 2025, doi:<a href="https://doi.org/10.1017/jfm.2025.362">10.1017/jfm.2025.362</a>. De Leo A, Brizzolara S, Cavaiola M, He J, Stocchino A. Rigid fibre transport in a periodic non-homogeneous geophysical turbulent flow. <i>Journal of Fluid Mechanics</i>. 2025;1011. doi:<a href="https://doi.org/10.1017/jfm.2025.362">10.1017/jfm.2025.362</a> De Leo, Annalisa, Stefano Brizzolara, Mattia Cavaiola, Junlin He, and Alessandro Stocchino. “Rigid Fibre Transport in a Periodic Non-Homogeneous Geophysical Turbulent Flow.” <i>Journal of Fluid Mechanics</i>. Cambridge University Press, 2025. <a href="https://doi.org/10.1017/jfm.2025.362">https://doi.org/10.1017/jfm.2025.362</a>. A. De Leo, S. Brizzolara, M. Cavaiola, J. He, A. Stocchino, Journal of Fluid Mechanics 1011 (2025). De Leo A, Brizzolara S, Cavaiola M, He J, Stocchino A. 2025. Rigid fibre transport in a periodic non-homogeneous geophysical turbulent flow. Journal of Fluid Mechanics. 1011, A5. 197292025-05-25T22:16:46Z2025-09-30T12:38:34Z