Numerical study of heat transfer enhancement of channel via vortex-induced vibration

Thermal diffusion in a developed thermal boundary layer is considered as an obstacle for improving the heat transfer rate of air-cooled heat sinks. In this work, a passive method using vortex-induced vibration (VIV) is introduced to disrupt the thermal boundary layer and thereby increase the heat transfer rate. A cylinder with a flexible plate is placed in a clean channel; the vortex shedding due to the cylinder gives rise to the oscillation of the plate downstream. The consequent flow-structure-interaction (FSI) strengthens the disruption of the thermal boundary layer by vortex interaction with the walls, and improves the mixing process. This novel concept is demonstrated by a two-dimensional modeling study at Re_D = 204.8, 245.7, 286.7, 327.7, and two inlet temperature profiles. The results indicate the VIV can significantly increase the average Nusselt (Nu) number, with a maximum enhancement of 90.1% over that of a clean channel.