Computational approaches to aspect-ratio-dependent upper bounds and heat flux in porous medium convection

Autor:	Charles R. Doering, Gregory P. Chini, Baole Wen, Navid Dianati
Rok vydání:	2013
Předmět:	Physics::Fluid Dynamics Physics Convection Aspect ratio Heat flux Mathematical analysis Direct numerical simulation General Physics and Astronomy Rayleigh number Porous medium Nusselt number Upper and lower bounds
Zdroj:	Physics Letters A. 377:2931-2938
ISSN:	0375-9601
DOI:	10.1016/j.physleta.2013.09.009
Popis:	Direct numerical simulation (DNS) has shown that Rayleigh–Benard convection in a fluid-saturated porous medium self-organizes into narrowly spaced plumes at (ostensibly) asymptotically high values of the Rayleigh number Ra. In this Letter a combination of DNS and upper bound theory is used to investigate the dependence of the Nusselt number Nu on the domain aspect ratio L at large Ra. A novel algorithm is introduced to solve the optimization problems arising from the upper bound analysis, allowing for the best available bounds to be extended up to Ra ≈ 2.65 × 10 4 . The dependence of the bounds on L ( Ra ) is explored and a “minimal flow unit” is identified.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::b112f60286afdaff9f2a57c2f36d84a8 https://doi.org/10.1016/j.physleta.2013.09.009 Zobrazit plný text záznamu Full Text from ScienceDirect