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Chjan Lim RPI, Troy, NY, US http://www.rpi.edu/~limc. Phase Transitions in Planetary atmospheres - a Shallow-Water Model and applications to Venusian super-rotation and giant spots on Jupiter. Based on joint work with X. Ding
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Chjan Lim RPI, Troy, NY, UShttp://www.rpi.edu/~limc Phase Transitions in Planetary atmospheres - a Shallow-Water Model and applications to Venusian super-rotation and giant spots on Jupiter Based on joint work with X. Ding Cf. Physica A 2006, J. Math Phys june 2007, Phys Fluids 08, SIAP 06 and book Vorticity, Stat Mech and MC Simulations, Springer Oct 2006
Collaborators and acknowledgement • Dr. Xueru Ding, PhD student at RPI • Support provided by US ARO and DOE • Based on paper submitted to Phys Fluids In april 2008 (with Xueru Ding) and Conf Proc of IUTAM Symp. Steklov Moscow 2006 (Plenary Talk)
Outline of talk on a unified theory • Major physical result 1- factors for anticyclonic dominance in coherent spots on Gas Giants • Major physical result 2 – factors for absence of sub-rotating nearly solid-body barotropic flows in slowly-rotating terrestrial planets • Orientation asymmetry in the Lagrangians • Exact solns by M. Kacs’ spherical model method
Recent debates • Marcus-Sommeria-Swinney 1980s – 1990 supports QG model which does not have anticyclonic asymmetry but provide a closer fit to rim velocities in GRS • Williams-Yamagata-Antipov 1980 – 1990 favors the IG regime in SWE due to this asymmetry.
Lagrangian • Lagrangian is : L = KE + PE = KE_r + AM + IM + PE “=“ (u . u) + (u . u_p) + (u_p . u_p) + gh^2
From Invariants to Constraints– invariants of unforced inviscid SWE H = KE_r + PE conserved; not L, so not AM + IM = L – H; must not fix L
Extension to freely-decaying SWE • All enstrophies (including higher vorticity moments) decay; Reduced energy / Hamiltonian H decays • For bdd (periodic) 2D domains, rigorous results for selective decay of quadratic enstrophy to minimum Dirichlet Quotient –related to dual cascades first proved by Foias and Saut 84, much later Majda-Wang 01 • Tea cup and Sommeria- van Heijst experiments suggest more than 2 separated time-scales in nearly-inviscid quasi-2D bdd flows – viscous time, Ekman pumping time and up-scale energy transfer time in inverse cascade • Rigorous results of Chemin, Grenier et al for quasi-2D rotating flows in bdd domains confirm at least 3 time-scales and that interior flow is inviscid.
Formulation of constraints • After choosing canonical –in-action L microcanonical constraints on circulations and enstrophies follow: • (a) enstrophies nearly const in fast time • (b) canonical on enstrophies give Gaussian – not good for phase transitions
Constraints Choose Action = L in path-integral form for Gibbs partition function; so H, AM, IM changes but not sum Fix 3 circulations – height h(x), rel vort, divergence; first by mass conservation and incompressibility; last 2 by Stokes on sphere Fix 2 quadratic enstrophies – rel vort and divergence instead of potential vorticity enstrophy
Classical energy-enstrophy models • Canonical in both energy and enstrophy (Kraichnan 1975) is a Gaussian model that is not well-defined for low temperatures. • Miller-Robert-Sommeria theories (1990s) conserves infinite number of enstrophies • Majda-Turkington (2000s) uses finite inequality constraints and apriori distributions on small scales
Restframe energy • For nondivergent barotropic fluid, the energy in the restframe
Energy II • Dropping the last – constant term – we get Second term is proportional to angular momentum
Coupled BV - BECondensation Super-Rotation
Coupled BV Monte-Carlo simulation results Sub-Rotation
Coupled BV – MC entropy Based on X. Ding’s algorithm for calculating degeneracy
Conclusions • Possible extensions to include time dynamics from one most probable state to another along the lines of S. Wang and T. Ma’s new work – looks promising from the GL example (JMP 08) • Many rigorous math results on existence of free energy minimizers for the Shallow Water Model – Direct methods of the C. of Variations