Langevin based turbulence model and its relationship with Kappa distributions

Sci Rep. 2022 Feb 8;12(1):2136. doi: 10.1038/s41598-022-05996-0.

Abstract

Kappa distributions (or [Formula: see text]-like distributions) represent a robust framework to characterize and understand complex phenomena with high degrees of freedom, as turbulent systems, using non-extensive statistical mechanics. Here we consider a coupled map lattice Langevin based model to analyze the relation of a turbulent flow, with its spatial scale dynamic, and [Formula: see text]-like distributions. We generate the steady-state velocity distribution of the fluid at each scale, and show that the generated distributions are well fitted by [Formula: see text]-like distributions. We observe a robust relation between the [Formula: see text] parameter, the scale, and the Reynolds number of the system, Re. In particular, our results show that there is a closed scaling relation between the level of turbulence and the [Formula: see text] parameter; namely [Formula: see text]. We expect these results to be useful to characterize turbulence in different contexts, and our numerical predictions to be tested by observations and experimental setups.