2025-09-11 カリフォルニア大学サンディエゴ校（UCSD）
＜関連情報＞
- https://today.ucsd.edu/story/turbulence-with-a-twist
- https://journals.aps.org/prl/abstract/10.1103/46g3-n7cx
体積力作用下における配管内の層流-乱流遷移を制御する三臨界指向性浸透現象 Tricritical Directed Percolation Controls the Laminar-Turbulent Transition in Pipes with Body Forces
Guru K. Jayasingh and Nigel Goldenfeld
Physical Review Letters Published: 3 September, 2025
DOI: https://doi.org/10.1103/46g3-n7cx
Abstract
The laminar-turbulent transition in straight pipes is believed to occur through a continuous nonequilibrium phase transition in the directed percolation universality class. However, in curved pipes or in the presence of body forces it is possible to observe a discontinuous transition and other phenomenology which seem inconsistent with the emerging consensus. Here, we consider the perturbing effects of body forces and incorporate them into a minimal Landau theory of the transition. We calculate the phase diagram as a function of Reynolds number and body force strength, and show that above a threshold strength of the latter, there is a tricritical point which accounts for the observed discontinuity behavior, including spatially heterogeneous states. Our results are consistent with recent experiments in centrifugal pipes and direct numerical simulations of heated flows.
