Chemically radiative aspects of mixed convection unsteady MHD stagnation point flow with Williamson nanofluid: Semi-numerical approach

The Williamson nanofluid exhibits a wide range of applications in the oil industry, geothermal reservoirs, and biomedical fields. The present study delves into the significant aspects of the heat and mass transfer phenomenon within the unsteady Williamson Buongiorno model over a stretching surface through a porous medium. The influence of magnetic field, thermal radiation, chemical reaction, Brownian motion, and thermophoresis coefficients on flow field are explored. The leading constitutive equations are converted to nonlinear, self-similar ordinary differential equations via appropriate similarity conversion equations. These resultant equations are solved using collocation strategies such as shifted Chebyshev collocation and Haar wavelet collocation techniques. The velocity profiles exhibit a decline in flow-assisting conditions while increasing in flow-opposing situations for the corresponding parameters except for mixed convection, solutal, and radiation parameters. The temperature profiles augment with mixed convection (flow opposing case) and radiation parameters; the contrasting nature of these profiles is noticed for other governing parameters. Concentration profiles initially intensify but subsequently decrease in the far-field flow region under both flow circumstances. The skin-friction coefficient reduces with growing parameters of radiation, mixed convection, Brownian motion, chemical reaction, Schmidt number, and reverse trend in the skin-friction coefficient is noticed for enhancement in remaining flow factors. • Heat and mass transfer traits in unsteady Williamson nanofluid flow over stretching sheet in a porous medium are presented. • The impact of MHD, mixed convection, Brownian motion, and thermophoresis on chemically radiative fluid flow is explored. • Mass flux conditions for nanoparticles are counted. • The system of self-similar equations is solved via shifted Chebyshev and Haar wavelet collocation techniques. • The Chebyshev polynomials are chosen due to the minimax property and Runge phenomenon.