Small scale structures of turbulence in terms of entropy and fluctuation theorems

Fundamental results in nonequilibrium thermodynamics are shown to be associated with small-scale features of turbulent flows. The estimation of entropies allows the selection of distinct realizations of turbulent cascade trajectories through a hierarchy of spatial scales. Entropy-consuming cascade trajectories lead to small-scale intermittent structures with piling up of velocity increments and finite ``jumps.'' This finding is of interest for fundamental questions on singularities or rare extreme velocity gradients.