Buoyancy driven vortex flow and thermal structures in a very low Reynolds number mixed convective gas flow through a horizontal channel

Abstract

This paper starts with an overview of the buoyancy driven vortex flow and the associated thermal characteristics in low Reynolds number mixed convection of gas through a bottom heated horizontal plane channel. Various vortex flow patterns reported in the past decades from theoretical, experimental and numerical explorations are examined, including the longitudinal, transverse and mixed vortex rolls. The mixed vortex rolls exist in several forms and result from the merging and/or splitting of the longitudinal and transverse rolls which are simultaneously present in certain parameter ranges. Then, the buoyancy induced formation of the longitudinal and transverse vortex flows from the unidirectional forced convection dominated flow in the channel is illustrated. Besides, the vortex flow affected by the aspect ratio of the channel is also discussed. Moreover, the stabilization of the unstable vortex flow driven at very high buoyancy-to-inertia ratios through the top plate inclination, top plate heating and a surface-mounted rib is inspected. Furthermore, our recent results for the mixed convective vortex flow structures over a heated circular substrate are presented. Finally, directions for future research are pointed out according to the need for thin film vapor phase epitaxy frequently used in microelectronic fabrication.