Hall and ion-slip effects on MHD flow of a Casson fluid past an impulsively rotating vertical porous plate with a ramped wall temperature and surface concentration

Abstract

This study investigates the flow behavior of a Casson fluid under specific conditions relevant to engineering, astrophysics, and biofluid mechanics. Blood, which exhibits Casson-fluid properties, interacts with magnetohydrodynamics (MHD), and understanding this behavior can aid in designing medical devices such as blood pumps and diagnostic tools for conditions like hypertension. The research examines the unsteady MHD free-convective rotational flow of an incompressible, electrically conducting Casson fluid over an impulsively moving, infinite, vertical porous plate. The study incorporates a ramped wall temperature and mass concentration while considering the effects of Hall current and ion slip. A uniform magnetic field is applied perpendicular to the flow direction, assuming a low magnetic Reynolds number, which renders the induced magnetic field negligible. The Rosseland approximation is used to model radiative-heat transfer in the energy equation. Analytical solutions to the governing equations are obtained using the Laplace-transform method. The influence of key parameters on velocity, temperature, and mass-concentration distributions is investigated through graphical representations. Additionally, shear stress, heat-transfer rates, and mass-transport rates are examined using tabulated data. Results indicate that Hall current and ion slip enhance the resultant fluid velocity. Significant differences in velocity profiles are observed between ramped and isothermal boundary conditions. Furthermore, this study has implications for thermal management in spacecraft components and industrial applications involving Casson fluids, such as molten plastics and polymers. The findings also provide insights into extrusion and molding processes under varying conditions.