Flow visualization using heat lines for unsteady radiative hydromagnetic Micropolar convection from a vertical slender hollow cylinder

Janardhana Reddy, G; Kethireddy, B; Beg, OA

Abstract

The present study aims to investigate the thermal radiation heat transfer effect on unsteady magnetohydrodynamic (MHD) flow of micropolar fluid over a uniformly heated vertical hollow cylinder using Bejan’s heat function concept. The normalized conservation equations emerge as a system of time-dependent non-linear coupled partial differential equations. Under appropriate wall and free stream conditions these equations are solved with an efficient unconditionally stable implicit scheme of Crank-Nicolson type. Important thermo-physical parameters featured include the magnetic body force parameter (M), Grashof (free convection) parameter (Gr), Eringen micropolar material parameter (K), Prandtl number (Pr), conjugate heat transfer parameter (P) and radiative-conductive Rosseland parameter (N), are analyzed on the flow-field with ranges 0-3, 105-106, 0-1.2, 0.7-7.0, 0-0.5 and 0-15, respectively. The time-histories of average values of momentum and heat transport coefficients, as well as the steady-state flow variables are presented for selected values of these non-dimensional parameters. With elevation in magnetic parameter or radiation parameter, the time taken for the flow-field variables to attain the time-independent state increases. The dimensionless thermal radiative heat function values are closely correlated with the overall rate of heat transfer on the outer hot cylindrical wall. Bejan’s heat flow visualization implies that the thermal radiative heat function contours are compact in the neighbourhood of leading edge of the boundary layer on the outer hot cylindrical wall. Increasing radiation or magnetic parameter values result in an increase in the deviation of heat lines from the hot wall. Also, the heatlines are observed to depart slightly away from the hot wall with greater values of vortex viscosity. Furthermore, the deviations of flow variables from the hot wall for a micropolar fluid are significant compared to the Newtonian fluid (vanishing micropolar vortex viscosity).

Citation

Janardhana Reddy, G., Kethireddy, B., & Beg, O. (2018). Flow visualization using heat lines for unsteady radiative hydromagnetic Micropolar convection from a vertical slender hollow cylinder. International Journal of Mechanical Sciences, 140, 493-505. https://doi.org/10.1016/j.ijmecsci.2018.03.014

• Journal Article Type: Article
• Acceptance Date: Mar 13, 2018
• Online Publication Date: Mar 14, 2018
• Publication Date: Mar 14, 2018
• Deposit Date: Mar 14, 2018
• Publicly Available Date: Mar 14, 2019
• Journal: International Journal of Mechanical Sciences
• Print ISSN: 0020-7403
• Publisher: Elsevier
• Volume: 140
• Pages: 493-505
• DOI: https://doi.org/10.1016/j.ijmecsci.2018.03.014
• Publisher URL: http://dx.doi.org/10.1016/j.ijmecsci.2018.03.014
• Related Public URLs: https://www.journals.elsevier.com/international-journal-of-mechanical-sciences