Generation of the Karman Vortex Street at the Low Reynolds Number Due to Natural Convection

The present numerical computations and flow visualizations showed the generation of the Karman vortex street and the change of its vortex shedding upon cooling a circular cylinder submerged in an upward free-stream of air at the low Reynolds number. The dominant causes of the generation of the vortex and the decrease of the Strouhal number in the opposing flow were made clear from points of view of changes of the kinematic viscosity, separation points, wake velocity, and vorticity upon cooling the cylinder.