Thermal transport in g-jitter-driven three-dimensional stagnation-point nanofluid flow with quadratic radiation and quadratic convection: corcione-based modeling and rsm sensitivity analysis

This work examines the unsteady three-dimensional stagnation-point flow and heat transfer of an Al₂O₃-water nanofluid across a surface, considering the combined influences of g-jitter, nonlinear thermal convection, suction, nonlinear thermal radiation, and viscous dissipation. To analyse the nanofluid's thermophysical characteristics using Corcione's correlations to account for influences of nanoparticle size, and with the help of semi-similar variables, we convert the governing nonlinear partial differential equations into a dimensionless system. The dimensionless system is solved numerically using the Keller-box technique, and the response surface approach quantifies skin-friction coefficient and Nusselt number sensitivity for 28 and 45 nm nanoparticle sizes. The nanoparticle volume fraction displays dual behaviour in velocity distributions, showing a decrease near the wall and an increase farther from the surface. Through the thinning of the hydrodynamic and thermal boundary layers, increasing suction reduces temperature and velocity. Sensitivity and RSM analyses indicate that suction dominates engineering responses, contributing 69.66%−69.74% to skin-friction coefficient variation and 64.34%−64.49% to Nusselt number. Radiation, with R d and Rd 2 , has the second strongest impact on heat transfer, contributing 23.40%−23.61%. Reducing nanoparticle diameter from 45 to 28 nm increases the average Nusselt number by 0.177%. The skin-friction coefficients barely increase by 0.0116% in the x − direction and 0.0177% in the y − direction. Aerospace cooling, microgravity thermal management, and stagnation-region heat-transfer optimisation may all benefit from these results.

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