Visualization of natural convection in a side-heated cavity: transition to the final steady state

Abstract

The flow evolving in a water-filled square cavity which is suddenly heated and cooled on the opposing sidewalls is observed by using the shadowgraph technique. The horizontal boundaries of the cavity are thermally insulating, while the heated and cooled vertical sidewalls are conducting. In a previous publication, the emphasis was on the very early stages of the flow development. As part of this initial evolution, two travelling wave groups were observed. The present paper continues the description of the flow development until a steady state is reached. A clear visualization of the interaction between the second wave group and the laminar intrusion flow across the roof of the cavity is given. The subsequent decay of the horizontal intrusion triggering the thermal stratification in the cavity core and the adjustment of the vertical boundary layer are also observed. The final state is characterized by waves which continuously travel along the boundary layers.