2008/04/16 by Mohammad Mehrafarin, Nima Pourtolami · 1 citation
Physics and Astronomy · #physics.flu-dyn #cond-mat.stat-mech
paper · pdf · doi:10.1103/physreve.77.055304
published as Phys. Rev. E 77, 055304(R), 2008 · To appear in Phys. Rev. E, Rapid Communications
arxiv created 2008/04/16 · arxiv updated 2011/07/04
Recently, by analyzing the measurement data of Nikuradze, it has been proposed (N. Goldenfeld, Phys. Rev. Lett. \bf96, 044503, 2006) that the friction factor, f, of rough pipe flow obeys a scaling law in the turbulent regime. Here, we provide a phenomenological scaling argument to explain this law and demonstrate how intermittency modifies the scaling form, thereby relating f to the intermittency exponent, η. By statistically analyzing the measurement data of f, we infer a satisfactory estimate for η (≈ 0.02), the inclusion of which is shown to improve the data-collapse curve. This provides empirical evidence for intermittency other than the direct measurement of velocity fluctuations.