Directed percolation and puff jamming near the transition to pipe turbulence

article Directed percolation and puff jamming near the transition to pipe turbulence published yes Grégoire M Lemoult author 4787FE80-F248-11E8-B48F-1D18A9856A87 Mukund Vasudevan author 3C5A959A-F248-11E8-B48F-1D18A9856A87 Hong Yan Shih author Gaute Linga author Joachim Mathiesen author Nigel Goldenfeld author Björn Hof author 3A374330-F248-11E8-B48F-1D18A9856A870000-0003-2057-2754 BjHo department Revisiting the Turbulence Problem Using Statistical Mechanics project The onset of turbulence in pipe flow has defied detailed understanding ever since the first observations of the spatially heterogeneous nature of the transition. Recent theoretical studies and experiments in simpler, shear-driven flows suggest that the onset of turbulence is a directed-percolation non-equilibrium phase transition, but whether these findings are generic and also apply to open or pressure-driven flows is unknown. In pipe flow, the extremely long time scales near the transition make direct observations of critical behaviour virtually impossible. Here we find a technical solution to that limitation and show that the universality class of the transition is directed percolation, from which a jammed phase of puffs emerges above the critical point. Our method is to experimentally characterize all pairwise interactions between localized patches of turbulence puffs and use these interactions as input for renormalization group and computer simulations of minimal models that extrapolate to long length and time scales. The strong interactions in the jamming regime enable us to explicitly measure the turbulent fraction and confirm model predictions. Our work shows that directed-percolation scaling applies beyond simple closed shear flows and underscores how statistical mechanics can lead to profound, quantitative and predictive insights on turbulent flows and their phases. Springer Nature2024 eng Nature Physics 1745-2473 1745-2481 00123230060000110.1038/s41567-024-02513-0 201339-1345 Lemoult GM, Vasudevan M, Shih HY, et al. Directed percolation and puff jamming near the transition to pipe turbulence. Nature Physics. 2024;20:1339-1345. doi:<a href="https://doi.org/10.1038/s41567-024-02513-0">10.1038/s41567-024-02513-0</a> Lemoult, G. M., Vasudevan, M., Shih, H. Y., Linga, G., Mathiesen, J., Goldenfeld, N., & Hof, B. (2024). Directed percolation and puff jamming near the transition to pipe turbulence. Nature Physics. Springer Nature. <a href="https://doi.org/10.1038/s41567-024-02513-0">https://doi.org/10.1038/s41567-024-02513-0</a> G. M. Lemoult et al., “Directed percolation and puff jamming near the transition to pipe turbulence,” Nature Physics, vol. 20. Springer Nature, pp. 1339–1345, 2024. G.M. Lemoult, M. Vasudevan, H.Y. Shih, G. Linga, J. Mathiesen, N. Goldenfeld, B. Hof, Nature Physics 20 (2024) 1339–1345. Lemoult, Grégoire M., et al. “Directed Percolation and Puff Jamming near the Transition to Pipe Turbulence.” Nature Physics, vol. 20, Springer Nature, 2024, pp. 1339–45, doi:<a href="https://doi.org/10.1038/s41567-024-02513-0">10.1038/s41567-024-02513-0</a>. Lemoult, Grégoire M, Mukund Vasudevan, Hong Yan Shih, Gaute Linga, Joachim Mathiesen, Nigel Goldenfeld, and Björn Hof. “Directed Percolation and Puff Jamming near the Transition to Pipe Turbulence.” Nature Physics. Springer Nature, 2024. <a href="https://doi.org/10.1038/s41567-024-02513-0">https://doi.org/10.1038/s41567-024-02513-0</a>. Lemoult GM, Vasudevan M, Shih HY, Linga G, Mathiesen J, Goldenfeld N, Hof B. 2024. Directed percolation and puff jamming near the transition to pipe turbulence. Nature Physics. 20, 1339–1345. 171282024-06-09T22:01:03Z2025-09-08T07:50:20Z