UNSTEADY FLOW OF WALTERS-B MAGNETO-NANOFLUID OVER A BIDIRECTIONAL STRETCHING SURFACE IN A POROUS MEDIUM WITH HEAT GENERATION

Abstract

Countless applications of viscoelastic nanomaterials in the engineering and industrial processes attracted our attention to investigate the unsteady three-dimensional flow of a Walters-B nanomaterial over a stretchable surface. Moreover, the surface was maintained at non-uniform temperature with the help of simultaneous heat sources, namely, the prescribed surface temperature (PST) and prescribed surface heat flux (PHF). The powers of thermophoresis and Brownian motion were also incorporated through a two-phase nanofluid model. Furthermore, significant contributions from the magnetic field, internal heat generator/absorber, and porous space were also accommodated. A suitable combination of the variables was used to convert the governing partial differential equations into ordinary differential equations in order to find the analytical solution through the homotopy analysis method. Finally, the obtained results are presented in the form of tables and various plots. For the authenticity of the modeling and solution procedure, a comparison benchmark was established with the previously published data and also with the numerical solution through the Keller-box method. It is hypothesized through the present contribution that the escalating amount of the thermophoresis parameter reduces the heat transfer rate, whereas the intensifying amount of the Brownian motion parameter improves the mass transfer rate for both of the heat sources (PST and PHF). Moreover, the growing amounts of the heat generation/absorption and Walters-B parameters increase the temperature of the nanomaterial. Furthermore, the thermal state of the nanomaterial and mass concentration are reduced through growing amounts of the temperature-controlling indices for both heat mechanisms (PST and PHF).

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