研究課題/領域番号 |
17K14594
|
研究機関 | 沖縄科学技術大学院大学 |
研究代表者 |
Cerbus Rory 沖縄科学技術大学院大学, 流体力学ユニット, 研究員 (10795347)
|
研究期間 (年度) |
2017-04-01 – 2020-03-31
|
キーワード | 乱流遷移 / 非平衡相転移 / 臨界指数 / 摩擦 |
研究実績の概要 |
The purpose of this project was to investigate a claim that the transition to turbulence in pipe flow can be mapped to a specific kind of non-equilibrium phase transition: Directed Percolation. The main interest in this investigation was that if this claim can be proved, then it can be combined with some of my other recent results to predict the average friction in transitional pipe flows. Along the way, I have also investigated the statistics of the localized structures that emerge during transition ("puffs" and "slugs") and have shown that they are indistinguishable from fully turbulent flows with some important caveats. This work has resulted in two manuscripts that are currently under review in prominent journals. I have also determined experimentally and numerically that if the Directed Percolation hypothesis is true, then it will have to include the effect of the length of the pipe (so-called "finite-size effects"). I am in the final stages of determining the role of pipe length on the transition and friction now.
|
現在までの達成度 (区分) |
現在までの達成度 (区分)
3: やや遅れている
理由
The status of the project is slightly delayed from the timeline that I had originally anticipated both because I took time to clarify the statistical structure of transitional pipe flow (resulting in two submitted manuscripts) as well as because I had not anticipated the important role of pipe length in the transition. I believe that this second factor enhances the interest of this work, although it will take longer to clarify.
|
今後の研究の推進方策 |
I will continue to perform experiments and simulations on transition flow, specifically measuring friction and comparing against the Direct Percolation predictions, for several pipe lengths. This is in order to clarify the role of pipe length (so-called "finite-size effects"). Already I have completed the study for two pipe lengths experimentally, and one pipe length numerically, but more pipe lengths are needed to determine the trends more confidently.
|
次年度使用額が生じた理由 |
Because I have not finished the main goal of the project: to determine the friction in transition by appealing to the hypothesis that the transition to turbulence in pipe flow behaves just like a Direct Percolation transition, I kept my travel funds in order to travel and present our results when they are finished.
|