MHD mixed convection flow of alumina - water nanofluid into a lid-driven cavity with different patterns of wavy sidewalls

This research investigates the numerical analysis of magnetohydrodynamic (MHD) mixed convection flow and heat transfer within a bottom lid-driven cavity filled with water-alumina (Al2O3) nanofluid. The cavity’s sidewalls exhibit a wavy profile and are maintained at distinct temperatures. Cavity domain exhibit distinct free and force convections. These wavy walls, characterized by zigzag shapes determined by various wave amplitudes and their ratios (wave form), create a dynamic thermal environment. The top and bottom surfaces remain flat and well-insulated, while forced convection is induced by the drag of the bottom wall from left to right at a constant speed. Additionally, the bottom wall is subjected to a vertical magnetic field. The system of equations is discretized using the finite difference method. The numerical solutions are derived by the Gauss-Seidel iterative method. The study primarily focuses on investigating the effects of key parameters, including the wavy wall geometry, solid volume fraction (0 ≤ φ ≤ 0.0003), Rayleigh number (10³≤ Ra ≤10^5), and Hartmann number (0 ≤ Ha ≤0.6). Numerical solutions are computed across different ranges of these parameters, and the obtained results are successfully validated against previous numerical studies. The findings reveal that higher Hartmann numbers and solid volume fractions lead to lower circulation rates and Nusselt numbers. Convection is markedly enhanced with higher amplitude and its ratios of the wavy sidewalls. The combined two-sinusoidal function with the wave amplitudes of 2.5 and 0.47 of provides the highest mean Nusselt numberof3.204 with the highest dimensionless stream function of 1.638. These results highlight the significant influence of the wave form on both flow and temperature distributions.