Thermal boundary layer flow and heat transfer in a differentially heated cavity with a thin fin on the sidewall

In this paper, a two-dimensional numerical simulation is carried out to investigate the thermal boundary layer flow in a differentially heated cavity with a thin fin at the mid height of the hot wall. It is found that the thin fin changes the transition of the thermal boundary layer flow. In the initial stage, a lower intrusion front forms, bypasses the thin fin, and strikes the intrusion under the ceiling. After the lower intrusion front is convected away, the trailing flow behind it reattaches to the thermal boundary layer. As the stratification in the cavity is enforced, the separation and shedding of the flow around the thin fin become unstable, and thus induce the instability of the thermal boundary layer flow. The transition of the thermal boundary layer flow ultimately approaches a periodic flow in the quasi-steady stage. Due to the instability of the thermal boundary layer triggered by the fin, the heat transfer through the hot wall is significantly enhanced