Quantitative Sensitivity Analysis of Hybrid Nanofluid Transport over a Convective Rotating Stretchable Disk with Variable Thermophysical Properties and chemical reaction

<title>Abstract</title> <p>The present study investigates the enhancement of thermal energy transfer in a hybrid nanofluid flow driven by a spinning and stretching Riga disk, incorporating the effects of chemical reactions and thermal radiation. The thermal performance is evaluated using silver and aluminum oxide nanoparticles dispersed in a water-based fluid. To increase the physical realism, the Darcy-Forchheimer model is applied to capture internal and porous media effects. Temperature-dependent viscosity and thermal conductivity are considered alongside a convective temperature boundary condition and a zero mass flux constraint. In addition to conventional velocity, temperature , and concentration analysis, a comprehensive sensitivity framework based on perturbation theory and tornado visualization is developed to quantitatively identify the dominant transport mechanisms governing heat and mass transfer characteristics. Scaling group transformations reduce the governing partial differential equations to a system of ordinary differential equations, which are then solved numerically using MATLAB’s bvp4c method. The thermophysical properties of the hybrid nanofluid are further analyzed through the Levenberg-Marquardt back-propagation technique. According to the sensitivity analysis, mass transport behavior is mostly dominated by 1 Brownian motion and thermophoretic effects, whereas the Biot number has the greatest impact on the Nusselt number. The suggested approach greatly improves the interpretability and prediction power of nonlinear nanofluid transport systems and offers a clear hierarchy of regulating physical factors.</p>