EFFECTS OF HALL CURRENT ON UNSTEADY MHD CONVECTIVE COUETTE FLOWOF HEAT ABSORBING FLUID DUE TO ACCELERATED MOVEMENT OF ONE OF THE PLATES OF THE CHANNEL IN A POROUS MEDIUM

摘要

An investigation of unsteady MHD convective Couette flow of a viscous, incompressible, electrically conducting, and temperature dependent heat absorbing fluid within a rotating vertical channel embedded in a fluid saturated porous medium taking Hall current into account was carried out. Fluid flow within the channel was induced due to accelerated movement of one of the plates of the channel. The exact solution for fluid velocity and fluid temperature was obtained in closed form by the Laplace transform technique. The expressions for shear stress at the moving plate and rate of heat transfer at both the moving and stationary plates of the channel were also derived. Asymptotic behavior of the solution for fluid temperature and fluid velocity was analyzed for small and large values of time to gain some physical insight into the flow pattern. The numerical values of fluid velocity and fluid temperature were displayed graphically whereas numerical values of shear stress at the moving plate and rate of heat transfer at both the moving and stationary plates of the channel were presented in tabular form for various values of pertinent flow parameters. Hall current, thermal buoyancy force, and permeability of the medium tended to accelerate fluid flow in both the primary and secondary flow directions whereas heat absorption had a reverse effect on it. Fluid temperature attained steady state when time t >= 0.6. Heat absorption tended to enhance rate of heat transfer at the moving plate whereas it had a reverse effect on the rate of heat transfer at the stationary plate.