乱流の激しい回転と分散を測定する
Benjamin W Zeff1, Daniel D Lanterman, Ryan McAllister
1Department of Physics, IPST and IREAP, University of Maryland, College Park, Maryland 20742-4111, USA.
Nature
|January 10, 2003
まとめ
乱流は,激しい渦巻きとストレスの爆発を示します. 新しい観測により,これらのイベントは急速なストレンスから始まり,その後は渦巻性の上昇が続き,乱流の断続性に関する洞察を提供することを明らかにしています.
科学分野:
- 流体力学 流体力学
- トルブルンスの研究
- ノン・ガウシアン統計とは別の統計です.
背景:
- 乱流の特徴は,高間隔性であり,激しい渦巻きとストレスの爆発が特徴です.
- コルモゴロフ理論はエネルギーカスケードを説明するが,非ガウスの断続性の原因は説明しない.
- 乱流の断続性は,化学物質の混合,圧力低下,空洞化,大気渦などに影響を及ぼします.
研究 の 目的:
- 乱流における高断続性の原因を調査する.
- 速度コンポーネントとグラデーションを同時に測定し,消散とエンストロフィーを決定します.
- 激しい乱暴な爆発の間のイベントのシーケンスを分析するために.
主な方法:
- 3つの速度コンポーネントと9つの速度グラデーションを小さな体積で同時に測定する.
- 流れの分散 (ストレイン) とエンストロフィ (渦) の分析.
- 測定の統計分析と個々のバーストの進化.
主要な成果:
- 典型的な激しい出来事の連続は,急速な菌株の成長から始まります.
- これに続いて,渦が上昇し,ストレッチが突然減少します.
- この研究は,渦巻爆発中の速度と速度グラデーションの詳細な観測を提供します.
結論:
- 観測されたストレンスと渦の配列は,乱流の断続性に関する新しい洞察を提供します.
- これらの特徴には2つの潜在的なメカニズムが提案されています:一貫した構造のアドベクションまたは局所的な原因.
- これらのメカニズムを理解することは,乱暴な現象の予測と制御に不可欠です.
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