Dynamical Origins for Non-Gaussian Vorticity Distributions in Turbulent   Flows
  We present results on the connection between the vorticity equation and the shape of the single-point vorticity PDF. The statistical framework for these observations is cast in form of conditional averages. The numerical evaluation of these conditional averages provides insights into the intimate relation of dynamical effects like vortex stretching and vorticity diffusion and non-Gaussian vorticity statistics. 
Michael Wilczek, Rudolf Friedrich