Abstract
This study examines turbulent natural convection in a differentially heated cavity containing a Cu-water nanofluid under an oblique magnetic field. The novelty lies in investigating the effects of turbulence, magnetic-field inclination and nanoparticle concentration over a wide range of governing parameters. The standard “
k-ε
” turbulence model was implemented and the problem was solved using the finite element method. Key parameters include Rayleigh number (
Ra
= 10
7
–10
9
), Hartmann number (
Ha
= 0–6400), magnetic field inclination angle (
γ
= 0−90°) and nanoparticle volume fraction (
φ
= 2–6%). Results demonstrate that heat transfer intensifies with increasing Rayleigh number, with the Nusselt number rising by 97.5% from
Ra
= 10
7
to 10
9
but reducing by 57.2% at
Ha
= 6400. An inclination angle of
γ
= 60° was found to optimize heat transfer, resulting in an 11% increase in the Nusselt number compared to
γ
= 0° at
Ha
= 6400. Furthermore, increasing the nanoparticle concentration improved the thermal performance, with the Nusselt number increasing by 25.1% as
φ
rose from 0.02 to 0.06. Overall, these findings indicate that heat transfer can be effectively controlled by precisely adjusting the external magnetic field and nanoparticle loading.