This paper investigates forced convection associated with the cross-flow of micropolar fluids
over a horizontal heated circular cylinder. The full conservation equations of mass, linear
momentum, angular momentum and energy are solved to give the details of flow and thermal
fields. Heat convection process are mainly influenced by Reynolds number, Prandtl number and
material parameters of micropolar fluid. The Reynolds number is considered up to 200 while the
Prandtl number is fixed at 0.7. The vortex viscosity is the only material parameter considered in
this study and is selected in the range from 0 to 5. The study has shown that generally the mean
heat transfer decreases as the vortex viscosity increases. The results have also shown that both the
natural frequency of vortex shedding and the amplitude of oscillating lift force experience clear
reduction as the vortex viscosity increases