[NCTS Physics Research Highlights] Hong-Yan Shih 'Directed percolation and puff jamming near the transition to pipe turbulence', Nature Physics 20, 1339-1345 (2024)

• 2024-10-04
• Chen, Jhan Yu 陳詹喻
• Chemical physics, physical chemistry, nanoscience and complex systems Interdisciplinary Research

Directed percolation and puff jamming near the transition to pipe turbulence
管狀紊流相變附近的定向滲透與團塊阻塞態

Grégoire Lemoult, Vasudevan Mukund, Hong-Yan Shih*, Gaute Linga, Joachim Mathiesen, Nigel Goldenfeld & Björn Hof
Nature Physics 20, 1339-1345 (2024)
DOI: https://doi.org/10.1038/s41567-024-02513-0

Recent theoretical and experimental studies have advanced progress in understanding the transitional turbulence and suggest that it is a directed percolation non-equilibrium phase transition, but whether it is generic in pipe flow is still unclear due to the limitation of the extremely long time scales near transition. Combining experimental measurements and numerical simulations and renormalization group analysis of minimal models, we find a jammed phase of puffs with pairwise interactions emerging above the critical point and confirm that the turbulent fraction follows the critical scaling of directed percolation. Our work shows that statistical mechanics can provide quantitative understanding and predictions to turbulent flows.

近年來紊流相變的研究在理論與實驗上皆有突破進展並顯示其屬於定向滲透的非平衡相變，然而在管流系統中因為時間尺度過長的侷限仍未有定論。我們結合管流實驗量測和簡化模型的數值模擬與重整化群分析，發現新的阻塞態並測量組成的紊流團塊之間的交互作用，證實其為定向滲透相變。我們的研究顯示統計力學能提供紊流系統定量上的了解並預測新相態。