MIXED CONVECTION FLOW OF MICROPOLAR FLUID OVER AN ISOTHERMAL PLATE WITH VARIABLE SPIN GRADIENT VISCOSITY

A steady two-dimensional mixed convection flow of viscous incompressib le micropolar fluid past an isothermal horizontal heated plate with un iform Free stream and variable spin-gradient viscosity is considered. With appropriate transformations the boundary layer equations are tran sformed into nonsimilar equations appropriate for three distinct regim es, namely, the forced convection regime, the free convection regime a nd the mixed convection regime. Solutions of the governing equations f or these regimes are obtained by an implicit finite difference scheme developed for the present problem. Results are obtained for the pertin ent parameters, such as the buoyancy parameter, xi in the range of 0 t o 10 and the vortex viscosity parameters, Delta = 0.0, 1.0, 3.0, 5.0 a nd 10.0 for fluid with Prandtl number Pr = 0.7 and are presented in te rms of local shear-stress and the local rate of heat transfer. Effects of these parameters are also shown graphically on the velocity, tempe rature and the couple stress distributions. From the present analysis, it is observed that both the momentum boundary layer and the thermal boundary layer increase due to an increase in the Vortex viscosity of the fluid.