Laminar vortex shedding behind a cooled circular cylinder

This paper addresses the functional demonstration of a hot air flow generator driven by convective heat transfer and the airflow behind a cooled circular cylinder in cross flow in the low velocity range. The wake flow was investigated experimentally using flow visualization, hot-wire anemometry, and laser Doppler anemometry. An evaluation of the free-stream velocity from the vortex shedding frequency was derived for the isothermal and non-isothermal cases and demonstrated using simple stroboscope measurements. The results confirm that cylinder cooling destabilizes the wake flow in air, i.e., the laminar steady regime can be changed into the vortex shedding regime, and the vortex shedding frequency increases as the cylinder temperature decreases. This thermal effect of cylinder cooling is consistent with its counterpart, the known effect of flow stabilization by cylinder heating. The effective temperature and effective Reynolds number concept have been further quantitatively evaluated, and the extension of their validity to the case of cooled cylinders has been confirmed.