急拡大部をもつ管路流れの振動流への遷移とその機構(安定性・乱流安定性(3),一般講演)

概要

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Nonlinear interaction of traveling waves induced due to instability of flow in a channel with two expanded sections is investigated numerically, where the two sections have different expansion rates. It is known that the flow in a channel with only one expanded section of larger expansion rate is more unstable than that through a section with a smaller expansion rate. We found that traveling waves induced due to convective instability in the upstream expanded section affect the stability of flow in the downstream region leading to transition of the entire flow, while waves induced in the downstream region just go out of the channel without influencing any affect on the flow upstream. The critical Reynolds number for the transition from steady to oscillatory flow is evaluated and discussed in terms of convective and absolute instabilities. The origin of the oscillation is also explored.
日本流体力学会の論文
2009-09-02