Coupled effects of variable permeability and adiabatic undulating walls on natural convective flow in a trapezoidal cavity: Finite element analysis

Abstract

Investigation of hydrothermal characteristics and entropy produced by change in diameter of circular cylinder positioned at the center of trapezoidal enclosure with undulated upper wall is conducted. Natural convection phenomenon is considered along with physical aspects of inclining magnetic field and permeable medium. Envisioning all these factors combined no such study is available which makes current problem novel. So, the premier intends to commence this artifact is to fill the existing gap by comprehensively disclosing the influence of governing transport parameters attained after mathematical modeling in dimensionless format. Entropy phenomenon is analyzed by estimating total entropy and average Bejan number. The numerical solution of modeled mathematical framework is attained by utilizing finite element based open-source software renowned as COMSOL. Wide range of flow concerning parameters are considered for instance, diameter of cylinder (0.10≤D1≤0.20), Prandtl number (0.015≤Pr≤7.00), Rayleigh number (103≤Ra≤105), Darcy number (10-5≤Da≤10-3) and Hartmann number (0≤Ha≤10) while, remaining parameters like angle of inclination (γ) and irreversibility ratio (ω) are fixed at 45° and 10-2 respectively. The influence of these parameters on distributions is interpreted by displaying streamlines and isotherms. After scrutinization of outcomes, it is deduced that average Nusselt number, total entropy and average Bejan number enhances up to 3.49 %, 1.86 % and 2.70 % respectively for situation when diameter of cylinder is increased from 0.10 to 0.20. Furthermore, 28.35 %, 43.06 % and 59.55 % decrement in previously stated quantities is revealed in comparative manner for hydrodynamic (Ha =0) and hydromagnetic (Ha ≠0) cases.