Double-Diffusive Convection in a Rotated Bi-Layered Square Cavity with Triangular Porous Inclusion

This study examines the numerical analysis of natural convection in a square bi-layered enclosure with double diffusion effect, including a triangular porous part. The triangular porous section is in contact with an aqueous fluid that is homogeneous and isotropic. The horizontal walls are adiabatic, impermeable, and constant, while other walls remain at uniform temperatures and concentrations. Results obtained through the finite element method (FEM) are presented in the form of contours and tables. The study explored the influence of the cavity's rotation angle and thermal conductivity ratio on heat transfer. Additionally, the effects of various Darcy and Rayleigh numbers on thermal conditions were analyzed. The Nusselt number at the interface between layers was determined. Increasing the ratio of thermal conductivity “ ” values from 0.1 to 10 transforms twisted thermal lines into vertical patterns, homogenizing temperature distribution, also, it increases the average Nusselt number and convective heat transfer specifically in . The greater rotational angle of the enclosure augments U and V velocity values and encourages the thermosolutal convective heat transfer. While the angle varies from 0 to 60°, it affects thermal behavior by twisting isotherms, resulting in sharper temperature gradients in the fluid layers when higher values are applied. Higher Rayleigh and Darcy values lead to an enhanced Nusselt number magnitude and better thermosolutal convective heat transfer with a 60° rotation angle, yielding the most pronounced enhancement in thermosolutal convection. However, excessive tilting beyond 30° dampens vertical velocity components. The impact of porous media was investigated, revealing that the presence of fluid in the porous media enhances heat transfer via convection. The findings demonstrate the critical role of geometric and thermo-physical parameters in optimizing heat and mass transfer in complex porous-fluid systems and validate that the solution approach aligns with prior research utilizing different numerical techniques.