Fluctuations of the Instantaneous Space Averages in Fragmentation with   Kolmogorov Time Scales
  We investigate the time behavior of the fragmentation model with Kolmogorov time scales and space contraction resembling the random $\beta$-model of turbulence. The space averages computed at any instant using the entire spatial realization of the velocity field are shown to fluctuate strongly in time, and in this sense they are not observable. The time averaging required to achieve the steady-state distributions in the case of constant energy supply are found. The fluctuations of the probability distribution functions (PDFs) have intermittency properties different from those of PDFs. 
Sergei E. Esipov