円柱背面熱伝達に及ぼす円柱の大きさの影響

An experimental study was made on heat transfer and flow characteristics behind circular cylinders with three different sizes, 10mm, 12mm and 14mm in diameter, under lower freestream turbulence. The Nusselt number obtained, when the Reynolds number was kept a constant value, increased as the cylinder diameter became larger. Moreover, experimental results showed that for the relatively large cylinder case (D=12mm), the laminar-to-turbulent transition region in the separated shear layer was shifted in the upstreamwise direction with an increase in the Reynolds number, while the transition of larger cylinder (D=14mm) was observed in the early stage. It was found, therefore, that the variation of cylinder diameter has an effect on the transition phenomenon of the separated shear layer, and the heat transfer performance behind circular cylinders is influenced by its behavior