The eddy heat-flux in rotating turbulent convection

G. Ruediger; P. Egorov; L. L. Kitchatinov; M. Kueker

doi:10.1051/0004-6361:20041670

paper

The eddy heat-flux in rotating turbulent convection

arXiv:astro-ph/0407385 · doi:10.1051/0004-6361:20041670

Abstract

The three components of the heat-flux vector $F = ρ C_{p} < u^{'} T^{'} > a r e n u m er i c a l l y co m p u t e df or a s t r a t i f i e d r o t a t in g t u r b u l e n t co n v ec t i o n u s in g t h e N I R V A N A co d e ina f l a t b o x . T h e l a t i t u d ina l co m p o n e n t$ F_θ $p r o v es t o b e n e g a t i v e (p os i t i v e) in t h e n or t h er n (so u t h er n) h e mi s p h er eso t ha tt h e h e a t a l w a y s f l o w s t o w a r d s t h e p o l es . A s a s u r p r i se, t h er a d ia l h e a t - f l ux$ F_r $p e ak s a tt h ee q u a t or r a t h er t hana tt h e p o l es (T a y l or n u mb er s O (1 0^{6})) . T h es am e b e ha v i or i so b ser v e df or t h er a d ia l t u r b u l e n ce in t e n s i t y$ <u_r^{\prime 2}> $w hi c h f or free t u r b u l e n ce i s a l so b e l i e v e d t o p e ak a tt h e p o l es (see E q . (19) b e l o w) . A s w ec an s h o w, h o w e v er, t h eco n se q u e n ceso f t hi s u n e x p ec t e d r es u l t (a l soo b t ain e d b y K a e p y l a e, K or p ian d T u o min e n 2004) f or t h e t h eor y o f d i f f er e n t ia l r o t a t i o na r es ma l l a s main l y t h e$ F_θ $i sr es p o n s ib l e t oso l v e t h e ‘ T a y l or n u mb er p u z z l e^{'} . I na l l o u r s im u l a t i o n s t h e a z im u t ha l co m p o n e n t$ F_ϕ $p r o v es t o b e n e g a t i v eso t ha tt h er o t a t in g t u r b u l e n ce p r o d u ces an w es tw a r d s d i r ec t e d a z im u t ha l h e a t - f l ux w hi c h s h o u l d b eo b ser v ab l e . F l u c t u a t i o n s w i t hhi g h er t e m p er a t u r e a r ee x p ec t e d t o b e an t i cor r e l a t e d w i t h t h e i r o w nan g u l a r v e l oc i t y f l u c t u a t i o n s . W e f in d t hi sr o t a t i o n - in d u ce d r es u l t a s u n d er s t an d ab l e a s t h e$ F_ϕ$ is closely related to the radial Λ-effect which is known to be also negative in stratified and rapidly rotating convection zones.

8 pages, 9 figures, Astron. Astrophys. (subm.)

The eddy heat-flux in rotating turbulent convection

Abstract

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