Thermophysical and Viscoelastic Effects on Magnetically Controlled Mixed Convection in Functional Porous Materials

Abstract

The reliability of heat-induced flow in porous materials is crucial for geothermal energy retrieval, subterranean thermal storage, and many renewable energy systems. This research investigates how heat radiation, magnetic fields, porous-media properties, and viscoelastic features collectively affect the onset of mixed-convection instability in a horizontal porous layer filled with a Kelvin–Voigt viscoelastic fluid. These fluids are relevant to subsurface and energy systems because polymeric substances, suspended particulates, and complex fluid–rock interactions can lead to non-Newtonian behavior. Comprehending the factors that trigger flow instability is crucial for ensuring efficient heat transfer, minimizing unwanted thermal stratification, and enhancing the sustained performance of geothermal and porous thermal systems. A linear stability framework assesses key instability conditions by examining the effects of the Hartmann number, Darcy number, Richardson number, Prandtl number, thermal radiation parameter, and viscoelastic coefficient. The analysis shows that these dimensionless variables substantially alter the interplay among buoyancy, viscous forces, magnetic damping, thermal diffusion, and elastic resistance.