From additive to transport noise in 2D fluid dynamics

Abstract Additive noise in Partial Differential equations, particular those of fluid mechanics, has relatively natural motivations. The aim this work is showing that suitable multiscale arguments lead rigorously, from a model with additive noise, to transport type noise. apply both small-scale random perturbations the acting on large-scale passive scalar and action former large scales itself. Our approach consists studying (stochastic) characteristics associated fluid, here modelled by stochastic 2D Euler equations their convergence infinite scale separation limit.