Cattaneo-Christov double diffusions (CCDD) in entropy optimized magnetized second grade nanofluid with variable thermal conductivity and mass diffusivity

Abstract

In this research communication, mathematical model is developed to scrutinize the two-dimensional magnetohydrodynamic boundary layer flow of non-Newtonian nanofluid (second grade) toward a permeable and stretchable Riga plate surface. To examined the thermal and solutal relaxation characteristics the proposed model of Cattaneo-Christov double diffusions (CCDD) model is supposed. Furthermore, variable thermal conductivity and variable mass diffusivity are accounted. In addition, the convective condition of heat transfer is involved. The concept of entropy generation is also highlighted. Formulation also consists of thermal radiation, mixed convection and thermophoresis. The resulting problems are computed by modern approach known as optimal homotopy analysis method (OHAM). OHAM is a powerful method to used for the series solution of highly non-linear equations in comparison to other analytical and numerical methods. Total square residual error is computed. Velocity distribution enhances for second grade fluid parameter but reverse trend is seen for larger estimation of inverse Darcy number. Temperature profile increases for larger estimation of thermal relaxation parameter and characterize temperature (ɛ1). Nanoparticles concentration decays for boost values of solutal relaxation parameter and characterize concentration (ɛ2). Physical arguments for important parameters of interest are organized.

Keywords

• Non-Newtonian (second grade) fluid model
• Cattaneo-Christov double diffusions (CCDD)
• Nanofluid
• Stretched Riga plate
• Temperature dependent thermal conductivity and mass diffusivity
• Entropy generation rate