This paper focuses on the effect of thermal radiation on unsteady free convection viscous incompressible clectrically conducting fluid with dissipative heat between two long vertical plates when the temperature of one of the plates oscillates about a constant non zero mean temperature. The governing equations are solved by regular perturbation technique. The expressions for the velocity field, temperature field, the skin friction at the plate and Nusselt number are obtained in non-dimensional forms. Computations are performed for a wide range of the governing flow parameters, viz., the Hartmann number, Grashof Number for heat transfer, Prandtl Number and Radiation parameter. The effects of these flow parameters on the velocity, temperature, skin friction and Nusselt number are presented graphically and results are discussed.
MHD, thermal radiation, nusselt number, skin friction, free convection
 S.Ostrach, Laminar natural-convection flow and heat transfer of fluids with or without heat sources in channels with constant wall temperature, Technical Report 2863, (1952), NASA, USA.
 W. Aung, Fully developed laminar free convection between vertical plates heated asymmetrically, Int. J. Heat and Mass Transfer, 15, (1972), 1577-1580.
 A. Compo, O. Manca and B. Morrone, Numerical investigation of the natural convection flows for low Prandtl fluids in vertical parallel-plates channels, ASME Journal of Applied Mechanics, 73, (2006), 497-502.
 A.K.singh, H.R.Gholani and V.M.Soundelkar,Transient free convection flow between two vertical parallel plates. Warme and Staffubertragung (Heat and mass transfer), 31, (1996), 329-331.
 B.K.Jha, A.K.singh and H.S.Takhar,Transient free convection flow in a vertical channel due to symmetric heating, International journal of Applied Mechanics and Engineering, 8(3), (2003), 497-502.
 Ahmed N.and Kalita D, MHD oscillatory free convective past a vertical plate in slip flow-regime with variable suction and periodic plate temperature. International Journal of Heat and Technology, 26(2), 85-92 (2008).
 Hossain, M.A. and H.S.Takhar, Radiation effects on mixed convection alonga vertical plate with uniform surface temperature, Heat Mass Transfer, 31-243-248 (1996).
 A.Raptis, Radiation and free convection flow through a porous medium, Int. Commun, Heat and mass transfer, 25, 289-295, (1998).
 A.Raptis and C.Pendikis, Radiation and free convection flow past a moving plate, Appl. Mech. Eng, 4, 817-821 (1999).
 R.D.Cess, The interaction of thermal radiation with free convection heat and mass transfer Int, J, of heat and mass transfer, 9, 1269-1277 (1966).
 S.Shivaiah and J.Anand Rao, Effects of Soret Dufour and thermal radiation on unsteady MHD free convection flow past an infinite vertical porous plate in the presence of chemical reaction, Int. J. of Appl. Math and Mech, 7(3), 58-76, (2011).
 U.S.Rajput and P.K.Sahu, Natural Convection in unsteady Hydromagnetic coutte flow through a vertical channel in the presence of thermal radiation, Int. J. of Appl. Math and Mech, 8(3), 35-56, 2012.
 M.Mecili and E.Mezaache, Analytical solution for slip flow-heat transfer in microtubes including viscous dissipation and axial heat conduction. International Journal of Heat and Technology. Vol. 31, No. 2, pp. 27-36 (2013).
 N.Ahmed, K.Sarma and D.P.Barua, Magnetic field effect on free convective oscillatory flow between two vertical parallel plates with periodic plate temperature, Applied Mathematical Sciences, Vol. 6, 2012, no. 39, 1913-1924.
 M.Narahari. Oscillatory plate temperature effects of free convection flow of dissipative fluid between long vertical parallel plates, Int. J. of Appl. Math and Mech., 5(3), (2009).
 Brewster, Q., Thermal Radiatve Transfer and Properties, John Wiley and Sons. Inc, New York, 1992.