Numerical Simulation of MHD Mixed Convection and Heat Transfer in a Lid-Driven Hexagonal Enclosure with a Heated Wavy Cylinder

Abstract

This study investigates magnetohydrodynamic (MHD) mixed convection flow in a lid-driven hexagonal cavity containing an inner heated wavy cylinder. The flow is assumed to be time-independent, laminar, and incompressible. The upper wall moves at constant velocity and is thermally insulated, while the inner cylinder is kept at high temperature and the outer walls are cold. The governing equations are nondimensionalized and solved using the finite element method with a Galerkin formulation in COMSOL Multiphysics, and the results are validated against benchmark solutions using streamlines and isotherms. Unlike conventional cavity configurations, the presence of a wavy heated cylinder significantly modifies both vortex dynamics and thermal transport. The results demonstrate that the wavy surface enhances localized thermal intensification and promotes the formation of asymmetric secondary vortices, which are strongly governed by the combined effects of Reynolds number (Re), Richardson number (Ri), and magnetic parameter (M). The interaction between lid-driven shear flow and buoyancy-driven convection induces a non-uniform redistribution of vortical structures, with more pronounced asymmetry in secondary vortices observed at higher Ri. The findings offer essential insights into the coupled thermo-fluid-magnetic interactions within this complex geometry, providing important guidance for the development of advanced thermal systems such as MHD-based heat transfer devices.

IUBAT Review—A Multidisciplinary Academic Journal, 9(1): 26-48