Thermal flow characteristics of an isolated vortex developed near the channel wall with a rectangular cylinder
| Autor: | Kazuki, Atarashi, Takuya, Fuse, Kyoji, Inaoka, Mamoru, Senda |
|---|---|
| Jazyk: | japonština |
| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | 同志社大学ハリス理化学研究報告 = The Harris science review of Doshisha University. 59(2):73-80 |
| ISSN: | 2189-5937 |
| Popis: | PIVとLIFを用いてチャネル乱流中に設置した正方形柱の後流における壁近傍の熱流動特性を調べた．断面平均流速と流路高さに基づくレイノルズ数は15000である．壁近傍の高渦度領域は，反時計回りに回転するカルマン渦によって巻き上げられ，間欠的に孤立渦に発達する．カルマン渦の移流速度は孤立渦のそれよりも大きいため，孤立渦はカルマン渦に取り込まれて消滅する．孤立渦は時計回りに回転する負の渦度を有しており，壁近傍で温められた流体は主流側へ供給され，また主流側から壁近傍領域に冷たい流体が輸送される．よって，主流側からの流体の巻き込みは壁近傍の流速を低減させると同時に熱伝達を促進し，運動量と熱の輸送の非相似性が現れることが明らかになった． Thermal flow characteristics near the wall of the channel flow past a square rod was studied with PIV and LIF. The Reynolds number based on the mean velocity and the channel height was 15000. It was found that the high vorticity layer near the channel wall is lifted by the counter-rotating Karman vortices and develops into the isolated vortex intermittently. Since the advection velocity of the Karman vortices is larger than that of the isolated vortices, the latter are engulfed into the Karman vortices. The isolated vortex has a negative vorticity rotating in the clockwise direction, and the fluid warmed near the wall is supplied to the main flow, and the fresh fluid is transported to the near-wall region from the mainstream. The fluid entrainment from the mainstream side reduces the flow velocity near the wall and at the same time promotes the heat transfer near the wall, resulting in the appearance of the dissimilarity between the momentum and heat transport. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|