Spectral local linearisation method for MHD Casson fluid on stratified bioconvective porous medium flow due to gyrotactic microorganisms

In this paper, the effect of hall parameter on the flow of Casson nanofluid containing gyrotactic microorganisms over a stretching boundary in a porous medium is studied. The stratification, porosity, and Casson fluid parameters are also examined. Using suitable similarity transformations, the basic equations describing the flow are converted to nonlinear differential equations, which are then solved computationally using the spectral local linearisation method. The effects of key parameters such as the Hall parameter, the thermophoresis parameter, the porosity parameter, and Casson fluid parameters are analyzed. The results obtained suggest that the Hall parameter has the effect of decreasing the secondary flow, the heat and mass transfer rate, and density of the motile microorganisms. A decrease in the the Hall parameter is found to cause an increase in the transfer rate, the mass transfer rate, and the density of the motile microorganisms. An increase in the porosity parameter leads to a decline in the skin friction, heat transfer rate, mass transfer rate, and density of the motile microorganisms. The applications of this study arise in industrial areas, including Hall current accelerators, planetary dynamics, Hall current sensors, and magnetohydrodynamic power generators.