正方形流路における非定常熱対流への遷移の予測 : 温度に対する境界条件の影響(<小特集>流れの不安定性・乱流遷移とその応用)

概要

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Transition from steady thermal convection to unsteady convection in a square channel heated from below is predicted by means of the secondary instability analysis. In the presence of a through flow, longitudinal roll is realized for the Reynolds number and the Rayleigh number above the critical values. It is steady and two-dimensional, and aligns along the channel. Linear stability of the longitudinal roll with respect to unsteady three-dimensional disturbances is examined numerically. Stability boundaries of the longitudinal roll are specified for the Prandtl number Pr=7 and for two kinds of thermal boundary conditions on the sidewalls. For the perfectly conducting sidewalls, the longitudinal roll is predicted to become unstable as a result of two kinds of instabilities. For the perfectly insulating sidewalls, the longitudinal roll is found to be stable for a wide range of the Reynolds number and the Rayleigh number, while additional two kinds of instabilities are found.
社団法人日本機械学会の論文
2002-04-25