Shear-and buoyancy-dominated heat transfer: Influence of plate speed and nanoparticles

This study conducts a detailed numerical analysis of how the speed ratio (γ) affects thermal and flow behavior within a square cavity that incorporates a diagonally moving plate. The investigation spans forced, mixed, and natural convection regimes, characterized by Richardson numbers Ri = 0.1, 1, and 10. Both heating and cooling boundary scenarios are examined to assess their distinct roles in convective heat transfer. Results indicate that higher plate speed ratios enhance heat dissipation in forced and mixed convection, particularly when the plate is cooled, with minimal effects observed in natural convection settings. The average Nusselt number trends reinforce the conclusion that plate velocity significantly influences heat transfer in shear-dominated flows but has limited impact in buoyancy-dominated conditions. Additionally, introducing nanoparticles (φ = 0.05) leads to notable improvements in heat transfer, especially under strong shear effects. These insights underscore the potential of optimizing plate motion and nanoparticle concentrations to elevate thermal efficiency in advanced heat management applications.