The phenomenon of vortex-merging in two-dimensional hydrodynamics has been investigated through direct numerical simulations. The fast and local processes that occur during the turbulent relaxation of a randomly initialized system in periodic geometry have been examined. The analysis reveals that many of the coherent structures can be described by a local principle of maximization of entropy. The validity of this entropy principle has been further confirmed by time dependent statistics, using a contour-tracking technique. Possible implications for the description of persistent coherent vortices, commonly observed in the atmosphere, have been discussed.
Local relaxation processes and maximum entropy states in two-dimensional hydrodynamic turbulence
Primavera L;SERVIDIO, SERGIO;CARBONE, Vincenzo
2010-01-01
Abstract
The phenomenon of vortex-merging in two-dimensional hydrodynamics has been investigated through direct numerical simulations. The fast and local processes that occur during the turbulent relaxation of a randomly initialized system in periodic geometry have been examined. The analysis reveals that many of the coherent structures can be described by a local principle of maximization of entropy. The validity of this entropy principle has been further confirmed by time dependent statistics, using a contour-tracking technique. Possible implications for the description of persistent coherent vortices, commonly observed in the atmosphere, have been discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.