Volume 114, Number 5, June 2016
|Number of page(s)||6|
|Published online||08 July 2016|
Entropy production and Fluctuation Relation in turbulent thermal convection
1 Department of Electrical, Management and Mechanical Engineering, University of Udine - 33100, Udine, Italy
2 Institute of Fluid Mechanics and Heat Transfer, Technische Universität Wien - 1060 Wien, Austria
3 Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 7190, Institut Jean Le Rond d'Alembert F-75005 Paris, France
Received: 9 February 2016
Accepted: 15 June 2016
We report on a numerical experiment performed to analyze fluctuations of the entropy production in turbulent thermal convection, a physical configuration taken here as a prototype of an out-of-equilibrium dissipative system. We estimate the entropy production from instantaneous measurements of the local temperature and velocity fields sampled along the trajectory of a large number of pointwise Lagrangian tracers. The entropy production is characterized by large fluctuations and becomes often negative. This represents a sort of “finite-time” violation of the second principle of thermodynamics, since the direction of the energy flux is opposite to that prescribed by the external gradient. We clearly show that the entropy production normalized by a suitable small-scale energy verifies the Fluctuation Relation (FR), even though the system is time-irreversible.
PACS: 05.20.Jj – Statistical mechanics of classical fluids / 05.40.-a – Fluctuation phenomena, random processes, noise, and Brownian motion / 47.27.-i – Turbulent flows
© EPLA, 2016
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.