Transient thermal transport in a wavy octagonal domain filled with nanofluids under various thermal boundary conditions

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This study investigates transient thermal transport and MHD behavior in a two-dimensional, unsteady natural convection system within a wavy octagonal enclosure filled with nanofluids containing various nanoparticle shapes. The bottom wall is exposed to different thermal boundary conditions (TBC), the top wall is cold, and the remaining boundaries are adiabatic. The governing equations are solved using the finite element method. Among the 32 types of nanofluids and five different nanoparticle shapes, Ag-kerosene with blade nanoparticles exhibits the optimal thermal performance and is selected for further analysis. The results, presented concerning average Nusselt number (Nuavg), streamlines, and isotherms, expose reduced thermal efficiency with increasing Lorentz force, while buoyancy force and ϕ enhance it. Additionally, among various TBC, uniform TBC leads highest percentage increase in heat transfer as ϕ increases. Moreover, with the coefficient of determination (R2) values of 95.45% for the response function, statistical analysis validates the model’s resilience.