抄録
The effect of the cavity aspect ratio on the flow and heat transfer characteristics is investigated numerically in this paper. The cavity is part of the channel’s lower wall heated at a uniform temperature. The approach is based on the low Reynolds Stress-omega turbulence model. The study is performed at two different Reynolds numbers. Results show that the flow structure depends heavily on the cavity aspect ratio. The increase of the aspect ratio enhances the heat transfer. In addition, the increase of the Reynolds number does not affect the flow structure but improves the heat transfer. To examine the effect of the cavity presence, we compared the local Nusselt number along the cavity walls to the one along the upstream wall. The heat transfer rate was found to be lower within the cavity but superior in the region located just downstream. In addition, the maximum value of the Nusselt number is observed at the reattachment region of the cavities characterized by the shear layer reattachment. At last, we note a clear correlation between the local Nusselt number and the velocity fluctuations profiles. This demonstrates a close relationship between these quantities.
