Inverse cascade in two-dimensional turbulence: deviations from Gaussianity

Abstract

High resolution numerical simulations of stationary inverse energy cascade in two-dimensional turbulence are presented. Deviations from Gaussianity of velocity differences statistics are quantitatively investigated. The level of statistical convergence is pushed enough to permit reliable measurement of the asymmetries in the probability distribution functions of longitudinal increments and odd-order moments, which bring the signature of the inverse energy flux. Their scaling laws do not present any measurable intermittency correction. The seventh order skewness is found to increase by almost two orders of magnitude with respect to the third, thus becoming of order unity.