Towards the dynamics of a radiative-reactive magnetized viscoelastic nanofluid involving gyrotactic microorganisms and flowing over a vertical stretching sheet under multiple convective and stratification constraints

Abstract

Due to the impressive industrial applications and continuous progress in the bio-nano-technological sector, the survey of MHD bioconvective flows in non-Newtonian nanofluids become nowadays the main subject of interest as this topic requires a wide range of physical importance in biofuel, bioengineering, and biomedical investigations. Motivated by the aforesaid applications, the present examination has been accomplished numerically to explore the interesting aspects of two-dimensional Walters-B nanofluid flows past a vertical elongating sheet, in which motile microorganisms swim within the medium. Herein, Buongiorno's nanofluid model has been extended realistically by adopting the modified version of Fourier’s and Fick's theories to evidence the significant roles of the haphazard motion/thermo-migration of the solid nanoparticles, the bioconvection phenomenon, the radiative heat transfer processes, and the activation energy on the flow problem under consideration. Further, the monitoring conservation equations were altered into a set of simplified differential equations via various mathematical transformations. By applying special differential quadrature schemes, the obtained nonlinear problem was tackled numerically in MATLAB software. Dynamically, it was proved that the viscoelastic parameter has a slow-down effect on the nanofluid motion, but its velocity can be speeded up enormously by upsurging the velocity ratio parameter. As other findings, it was found that the involved Biot numbers exhibit an enhancing effect on the sketches of the nanofluid temperature, the nanoparticles’ concentration, and the motile microorganisms’ concentration, whilst a reverse trend was revealed for the relaxation parameters against the thermal and nanoparticles’ concentration profiles.