Structure of a two-dimensional vortex behind a highly heated cylinder

The two-dimensional vortex structure behind a highly heated cylinder has been studied experimentally. The air velocity was set at 1.0 m/s. The surface temperature of the heated cylinder was varied up to 600°C. Particle image velocimetry (PIV) was used to measure the two-dimensional instantaneous and average velocities. Just downstream of the heated cylinder, the vortex was intensified by increasing the wall temperature of the heated cylinder. The vortex frequency decreased when the wall temperature increased. This indicates that the local kinematic viscosity plays a key role in the vortex structure. As a result, the vortex frequency of the heated cylinder can be expressed as a function of the Strouhal and Reynolds numbers, when the local kinematic viscosity is reasonably estimated by taking into account the effect of the wall heating.