Introduction
Intermittency is a common phenomenon in many complex systems, and we will see that it is a natural consequence of cascades, in the same way that exponentially growing solutions are properties of linear ordinary differential equations.
As in that case, the simplest theory leads to infinities and, also as in differential equations, it is limited in the real world by the appearance
of non-linearity and of spatial effects. In turbulence the term "intermittent" had been introduced by [Batchelor, G. K., & Townsend, A. A, 1949][1], in order to describe the distribution of the vorticity field. The definition of the intermittency vary from an author to another. It had been used to describe the variation of the energy flux. It had also been used by [Pope, S. B, 2001][2] as an interface between a turbulent and non turbulent region.
