Gaussian paradox and clustering in intermittent turbulent signals

Abstract

A relation between intermittency and clustering phenomena in velocity field has been revealed for homogeneous fluid turbulence. It is described how the intermittency exponent can be split into sum of two other exponents. One of these exponents (cluster-exponent) characterizes clustering of the 'zero'-crossing points in nearly Gaussian velocity field and another exponent is related to the tails of the velocity probability distribution. The cluster-exponent is uniquely determined by the energy spectrum of the nearly Gaussian velocity field and entire dependence of the intermittency exponent on Reynolds number is determined by the cluster-exponent.