Entropy fluctuations in shell models of turbulence

This letter concerns the extension to non-reversible systems of a relation between the statistics of the fluctuations of the entropy production rate and its stationary average. In the framework of a standard shell model of turbulence, we consider the statistics of the energy input rate and entropy supplied separately and provide numerical evidence that even though the fluctuations of the former quantity are consistent with the linear part of the fluctuation theorem, this is not so of the latter when the fluctuations are large enough. Moreover, in the linear regime, the slope is not in agreement with the universal value predicted by the theorem. Our results extend those of Aumaitre et al.