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In this work, we report the analysis of the higher order Lagrangian statistics in laboratory two- dimensional turbulence for a broad range of experimental conditions from chaotic flow to turbulence. Our results show that fluid particle dispersion is diffusive and it is determined by a single measurable Lagrangian scale related to the forcing scale in the turbulent range [1]. Higher order moments of the particle dispersion show strong self-similarity in fully developed turbulence [2]. Here we introduce a new dispersion law that describes single particle dispersion during the turbulence development [3]. These results offer a new way of predicting dispersion in turbulent flows in which one of the low energy scales are persistent. It may help better understanding of drifter Lagrangian statistics in the regions of the ocean where small scale coherent eddies are present [4].
References 1.H. Xia, N. Francois, H. Punzmann, and M. Shats, Lagrangian scale of particle dispersion in turbulence, Nature Communications, 4, 2013 (2013). 2.R. Ferrari, A.J. Manfroi , W.R. Young, Strongly and weakly self-similar diffusion, Physica D 154 111 (2001). 3.H. Xia, N. Francois, H. Punzmann and M. Shats, Taylor particle dispersion during transition to fully developed two-dimensional turbulence, Physics Review Letters, 112, 104501 (2014). 4.J.H. LaCasce, Statistics from Lagrangian observations, Progress in Oceanography, 77, 1 (2008). |