2011/01/31 by Maksim Sipos, Nigel Goldenfeld · 1 citation
Physics and Astronomy · #physics.flu-dyn
paper · pdf · doi:10.1103/physreve.84.035304
published as Phys. Rev. E 84, 035304(R) (2011) · 4 pages, 4 figures. See http://guava.physics.uiuc.edu/projects/Turbulence/dp.html for associated videos
arxiv created 2011/07/13 · arxiv updated 2013/01/07
We show that Directed Percolation (DP) simulations in a pipe geometry in 3+1 dimensions fully capture the observed complex phenomenology of the transition to turbulence. At low Reynolds numbers (Re), turbulent puffs form and spontaneously relaminarize. At high Re, turbulent slugs expand uniformly into the laminar regions. In a spatiotemporally intermittent state between these two regimes of Re, puffs split and turbulent regions exhibit laminar patches. DP also captures the main quantitative features of the transition, with a superexponentially diverging characteristic lifetime below the transition. Above the percolation threshold, active (turbulent) clusters expand into the inactive (laminar) phase with a well-defined velocity whose scaling with control parameter (Reynolds number or percolation probability) is consistent with experimental results. Our results provide strong evidence in favor of a conjecture of Pomeau.