Numerical simulation of periodic mixed convective heat transfer in a rectangular cavity with a vibrating lid

Periodic behavior of the mixed convective flow in a rectangular cavity with a vibrating lid is investigated numerically in this study. The periodic flow patterns and heat transfer characteristics found are discussed with attention being focused on the interaction between the frequency of the lid velocity vibration and the frequency of the natural periodic flow. Several practical cases are investigated to evaluate the effects of the frequency of vibration of lid velocity (W) at Re = 100 and Gr = 5 × 105. The frequency of the natural periodic flow can be most clearly seen when the lid is moved at a constant-velocity (without vibration). As the vibration is imposed on the lid with the dimensionless frequency of the lid velocity varied between 0.1 and 0.3, the combined effects of the natural frequency and the lid vibration frequency on the transient variations in the flow and the thermal characteristics have been observed. When the dimensionless frequency of lid velocity vibration is increased to be equal to or higher than 0.4, the natural periodic flow frequency disappears, and the lid vibration frequency dominates the flow field, which means that the periodic flow field has locked-on to the lid vibration.