Numerical Simulation for Bioconvection of Unsteady Stagnation Point Flow of Oldroyd-B Nanofluid with Activation Energy and Temperature-Based Thermal Conductivity Past a Stretching Disk

A mathematical modeling is explored to scrutinize the unsteady stagnation point flow of Oldroyd-B nanofluid under the thermal conductivity and solutal diffusivity with bioconvection mechanism. Impacts of Joule heating and Arrhenius activation energy including convective boundary conditions are studied, and the specified surface temperature and constant temperature of wall (CTW) are discussed. The consequences of thermal conductivity and diffusivity are also taken into account. The flow is generated through stretchable disk geometry, and the behavior of non-linear thermal radiation is incorporated in energy equation. The partial differential equations governing the fluid flow in the structure is reduced into dimensionless nonlinear ODEs by applying suitable similarity variables. The obtained system of non-dimensional nonlinear ODEs is treated numerically with the help of bvp4c solver in Matlab under shooting algorithm. The impact of various prominent parameters on velocity profile, thermal profile, volumetric nanoparticle concentration and microorganism distribution is depicted in graphical form. The numerical outcomes for skin friction coefficient, heat transfer rate, Sherwood number as well as microorganism density number versus various parameters are listed in the tables. The results show that fluid velocity is reduced by increasing buoyancy ratio parameter, while the fluid flow increases with mixed convective parameter. The temperature profile is enhanced with the amount of nonlinear thermal radiation and temperature dependent thermal conductivity. Furthermore, concentration profiles of nanoparticles have opposite behavior for Brownian motion coefficient and thermophoresis diffusion parameter, and it is noticed that by varying Peclet number the microorganisms profile is declined. The proposed study is useful to control and optimize heat transfer in industrial applications.