Change in viscosity of Williamson nanofluid flow due to thermal and solutal stratification

Current analysis is devoted to explore the computational aspects of variable viscosity on Williamson nanofluid over a non-linear stretching sheet. Viscosity of the fluid is assumed to be depend on temperature and due to thermal stratification, viscosity of the fluid also depends upon thermal diffusion. The basic mathematical problem (system of PDEs) is converted into non-linear ODEs via applying suitable transformations. Computational solutions of the problem is achieved by efficient numerical approach (shooting method). Characteristics of controlling parameters i.e. Lewis number, thermophoresis parameter, Hartmann number, plastic dynamic viscosity parameter, Weissenberg number, Prandtl number, stretching index, Brownian motion parameter, Prandtl number, thermal and solutal stratification parameters are plotted on concentration, velocity and temperature gradients. Furthermore friction factor coefficient, heat and mass diffusion rates are presented through graphs and tables. Conclusions are made on the basis of entire investigation and it is seen that velocity profile reduces for large values of variable viscosity and thermal stratification parameters while thermal stratification parameter shows opposite behavior for temperature profile. Moreover, concentration profile reduces for enhancing values of Lewis number and increases for large values of stretching velocity parameter. (C) 2018 Elsevier Ltd. All rights reserved.