On magnetohydrodynamics free convective flow within coaxial cylinder due to nonlinear thermal radiation in an isothermal/isoflux condition

Abstract

A theoretical exploration was reported to highlight the electrically viscous conducting fluid within a coaxial cylinder. Both the outer surface of the inner cylinder and the inner surface of the outer cylinder were porous, heated, and cool, respectively. The action of a simultaneous radial transverse magnetic field and velocity slip were imposed across the coaxial cylinder. For appropriate insight into the physical problem, the thermal Rosseland diffusion approximation was used to indicate the radiative heat flux in the energy equation. The aim is to investigate the effects of isothermal and isoflux conditions on slip-upshot heat transfer in a vertical coaxial cylinder due to nonlinear thermal radiation. The steady-state and unsteady solutions of the physical problem were provided and solved via regular perturbation and implicit finite different domains, respectively. It was noted that the magnetic and suction parameters reduced the fluid velocity and skin friction under both isothermal and isoflux conditions. Conversely, the Grashof number, thermal radiation, and injection parameters increased the fluid velocity, fluid temperature, and skin friction, with a more significant effect observed under isothermal conditions on the surfaces of the coaxial cylinder. Additionally, the sensitivity analysis revealed that the radiation parameter is highly sensitive under isothermal conditions, followed by the temperature difference parameter. In contrast, under isoflux conditions, the injection parameter shows extreme sensitivity, with the radiation parameter being the next most sensitive. The result reveals an excellent agreement between the analytical and numerical results at maximum time.