Intermittency in forced two-dimensional turbulence

Abstract

We find strong evidence for intermittency in forced two dimensional (2D) turbulence in a flowing soap film experiment. In the forward enstrophy cascade the structure function scaling exponents are nearly indistinguishable from 3D studies. Intermittency corrections are present in the inverse energy cascade as well, but weaker. Stretched exponential tails of the velocity difference probability distribution functions and shock like events at large velocity differences also resemble 3D studies. For decaying turbulence, where only the forward enstrophy cascade remains, all signs of intermittency disappear.