Buoyancy driven flow of a couple stress fluid from an isothermal vertical plate: the role of spatially periodic magnetic field

The present article deals with the analysis of the buoyancy-driven flow of a non-Newtonian couple stress fluid from an isothermal vertical plate under the influence of a spatially periodic magnetic field. We consider, in this work, the applied magnetic field to be a sinusoidal function of axial coordinate. We solve the coupled nonlinear governing equations numerically consistent with the help of an implicit Crank-Nicolson finite difference scheme. We analyse the impact of periodic magnetic field on the flow velocity of couple stress fluid and its eventual consequence on the convective transport of heat. The flow variables governing the underlying thermo-magneto-hydrodynamics are examined graphically in terms of velocity, temperature distribution, and friction-factor coefficients. The result indicates that the magnitude of the velocity and temperature increases for increasing the magnitude of the couple stress parameter, attributed primarily to the enhanced resistance due to larger degree collision of couple stress fluid particles. On the other hand, the local skin friction coefficient and heat transfer rate reduces owing to the adverse effect of the Lorentz force due to the applied magnetic field.