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SUMMARY:Statistical stability arguments for maximum kinetic energy dissipa
 tion - Bertram\, J (Australian National University)
DTSTART:20131031T170000Z
DTEND:20131031T173500Z
UID:TALK48627@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:The hypothesis that stationary turbulent flows have maximal me
 an-flow kinetic energy dissipation (Max-D) is intriguing because mean-flow
  properties can be predicted without modelling the turbulent component of 
 the flow. Our knowledge of Max-D is largely restricted to relatively simpl
 e laboratory flows. Measured Poiseuille flow profiles match Max-D predicti
 ons closely and\, under these simplified conditions\, Malkus's statistical
  stability argument provides some theoretical justification for Max-D [1].
  However\, it is not clear whether Max-D is applicable to more complicated
  fluid systems\, like Earth's atmosphere [2]. Recent global climate model 
 simulations have found that the calibrated values of important tunable par
 ameters are indeed consistent with Max-D [3]. Furthermore\, the maximum en
 tropy framework [4]\, which naturally gives a Max-D principle in the case 
 of simple laboratory flows\, can be readily applied to more complicated sy
 stems. I will discuss attempts to gener alise the Malkus statistical stabi
 lity argument and how this connects with maximum entropy arguments. In doi
 ng so I hope to compare the physical insights of statistical stability\, w
 hich emphasises dynamical resilience to perturbations\, with maximum entro
 py considerations\, which ignore system dynamics.\n\n[1] W. V. R. Malkus. 
 Borders of disorder: In turbulent channel ow. Journal of Fluid Mechanics\,
  489:185{198\, 2003. [2] Richard Goody. Maximum entropy production in clim
 ate theory. Journal of the atmospheric sciences\, 64(7):2735-2739\, 2007. 
 [3] Salvatore Pascale\, Jonathan M. Gregory\, Maarten H.P. Ambaum\, and Re
 mi Tailleux. A parametric sensitivity study of entropy production and kine
 tic energy dissipation using the FAMOUS AOGCM. Climate Dynamics\, 38(5-6):
 1211-1227\, 2012. [4] Dewar R and Maritan A. A theoretical basis for maxim
 um entropy production. 2013. In Beyond the Second Law: Entropy Production 
 and Non-equilibrium Systems (eds. R Dewar\, C Lineweaver\, R Niven\, K Reg
 enauer-Lieb)\, Springer\, In Press\n\n
LOCATION:Seminar Room 1\, Newton Institute
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