2026-03-11 沖縄科学技術大学院大学
10万個の球状粒子と数億点の3次元流体格子からなる、重力によって下方へ沈降する流体シミュレーションのレンダリング画像。© タンドゥレラほか（2026年）より改変
＜関連情報＞
- https://www.oist.jp/ja/news-center/news/2026/3/11/how-fast-does-smoke-rise-rain-fall-and-supernova-explode
- https://journals.aps.org/prl/abstract/10.1103/tc5z-rxcf
乱流沈降における新しい混合形態 New Form of Mixing in Turbulent Sedimentation
Simone Tandurella, Marco Edoardo Rosti, Stefano Musacchio, and Guido Boffetta
Physical Review Letters Published: 11 March, 2026
DOI: https://doi.org/10.1103/tc5z-rxcf
Abstract
We study the sedimentation of finite-size inertial particles in a Rayleigh-Taylor-like setup using state-of-the-art direct numerical simulations. The falling particles are observed to produce two distinct regions: a leading mixing layer with a linear concentration profile followed by a bulk region of uniform density. Unlike classical RT turbulence, the mixing layer extension accelerates with an anomalous, noninteger exponent, while the bulk region moves at a constant velocity. A one-dimensional model based on a local hindered settling law accurately captures the observed dynamics and its dependence on the particle-to-fluid density ratio. The present Letter identifies a new regime of convective mixing which develops at the front of particle suspensions in sedimentation processes.
