Vibration Effects on the Average Heat Transfer Characteristics of the Natural Convection Field in a Square Enclosure.

Abstract

In order to study the chaotic behavior of the vibrational thermal convection in a square enclosure, calculation method and the feature of the average Nusselt number with vibration frequency were precisely examained. In the computation the Prandtl number, the Rayleigh number and the vibration Grashof number were held constant of 0.71, 104 and 106, respectively. The angular frequency of vibration was changed in the range between 10 and 7 680. The results showed that the phoenomena could be predicted with the calculation method adopted in this paper and the change in the time-dependent characteristics of surface-average Nusselt number with the angular frequency of vibration could be analyzed well with power spectra. This change was characterized by the five regimes proposed by Fu et al. Moreover it was clarified that the region where the hysteresis phenomena were detected corresponded to the one where the variation of the surface-average Nusselt number was irregular and aperiodic.