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Flow visualization of Rayleigh–Bénard convection for cubical cavity
Author(s) -
Vekamulla Narayana,
Rani Hari Ponnamma
Publication year - 2020
Publication title -
heat transfer
Language(s) - English
Resource type - Journals
eISSN - 2688-4542
pISSN - 2688-4534
DOI - 10.1002/htj.21757
Subject(s) - streamlines, streaklines, and pathlines , nusselt number , discretization , natural convection , mechanics , convection , rayleigh number , adiabatic process , flow (mathematics) , vector field , combined forced and natural convection , physics , geometry , thermodynamics , mathematics , mathematical analysis , reynolds number , turbulence
Natural convective flow of air inside the cubical cavity is investigated numerically. The temperature of the bottom wall is kept higher than that of top cold wall, and other four walls are assumed to be adiabatic. Attention has been paid to the convective discretization schemes, like upwind, QUICK, total variation diminishing, normalized variable diagram (NVD) schemes that are compared with respect to accuracy. The output is validated with respect to the results available in the literature. A parallel computing message passing interface code is adapted to run the simulations. From the results, it is observed that the NVD scheme gives better results among all the employed convective discretization schemes irrespective of the mesh structure. Thus, in this article, self filtered central differencing which is a family of NVD, is used. From the enormous output data, along with the streamlines, contours of isotherms, the new technique of energy pathlines, and field synergy are used to visualize the fluid flow and heat transfer mechanism arising in the system in the range of Ra from 10 3 to 10 6 . Free energy streamlines are observed with small Ra , whereas trapped energy streamlines are observed with high Ra . When Ra increases, synergy angle increases and implies that the synergy between the velocity vector and temperature gradient gets reduced and leads to increasing values of average Nusselt number ( Nu ).