Significance of a permeable semi-circular body and magnetic field on the double-diffusive traits

Abstract

This study delves into the occurrence of double-diffusive natural convection while being affected by a magnetic field within a cold square enclosure, containing a heated and concentrated semi-circular body made permeable. The fusion of both flat and curved boundaries, combined with the permeable attributes, stands as the central impetus driving this inquiry. The main aim is to scrutinize the impact of buoyancy force, permeability, magnetic field strength, and angle on the double-diffusive convection taking place inside and around the permeable structure. To achieve this, a comprehensive parametric investigation is undertaken, emphasizing the importance of Darcy number (Da), buoyancy ratio (BR), Hartmann number (Ha), and magnetic field angle (γM) in relation to the flow, heat, and concentration transfer. We utilize the Lattice Boltzmann method, incorporating the Darcy-Brinkmann-Forchheimer equation as a source term, to precisely address the complex flow within the porous medium. The results will provide insights into the importance of a semi-circular body with porous characteristics in the context of thermo-solutal convection influenced by magnetic effects. These findings hold practical significance in various applications, including electronic cooling, pollutant removal, and food processing industries. The inquiry discloses that elevating the buoyancy force, permeability, and the angle of the magnetic field leads to advantageous heat and concentration characteristics. Furthermore, positioning the magnetic force in opposition to gravity reduces the restraining impact of the magnetic force on the mean Nusselt number (NuM) and the mean Sherwood number (ShM). Remarkably, instances of unsteady behaviour are predominantly noted when the BR takes on a negative value, and these phenomena’s intensity and frequency are heightened by the Da and the γM. Remarkably, there are a few irregular spikes detected in the NuM and ShM, which can be attributed to the emergence of a strong singular vortex in the upper part of the enclosure.

Keywords

• Semi-circular obstacle
• Double-diffusion
• Magnetic effect
• LBM
• Permeable structure
• Unsteady