Effects of the Aspect Ratio of Vibrated Enclosures on the Thermal Convection Field and Chaotic Characteristics.

Abstract

In this paper the time-dependent characteristics of the thermal convection field in rectangular enclosures with large aspect ratio exposed vertical vibration were numerically examined and the results were compared with the ones of square enclosure. 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 normalized angular frequency of forced vibration was changed in the range between 10 and 7680. As a result, it was ascertained that the five regimes with respect to the angular frequency proposed by Fu and Shieh for the square enclosure captured the change of surface-average Nusselt number when the chaotic characteristics were considered. It was also revealed that the vortices in the enclosure aligned to the vertical direction in the enclosure with large aspect ratio determined the characteristics of the surface-average Nusselt number on hot and cold side walls.