2006/08/25 by A. Duggleby, Andrew Duggleby, K. S. Ball +6
Engineering · Environmental Science · Physics and Astronomy · #Aerodynamics and Acoustics in Jet Flows #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Turbulent Flows #Plant Water Relations and Carbon Dynamics #physics.flu-dyn
paper · pdf · doi:10.48550/arxiv.physics/0608259
8 pages, 20 figures. First post-review update
openalex publication_date 2006/08/25 · arxiv created 2007/01/23 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The dynamical behavior of propagating structures, determined from a Karhunen-Lo`eve decomposition, in turbulent pipe flow undergoing reverse transition to laminar flow is investigated. The turbulent flow data is generated by a direct numerical simulation started at a fully turbulent Reynolds number of Reτ=150, which is slowly decreased until Reτ=95. At this low Reynolds number the high frequency modes decay first, leaving only the decaying streamwise vortices. The flow undergoes a chugging phenomena, where it begins to relaminarize and the mean velocity increases. The remaining propagating modes then destabilize the streamwise vortices, rebuild the energy spectra, and eventually the flow regains its turbulent state. Our results capture three chugging cycles before the flow completely relaminarizes. The high frequency modes present in the outer layer decay first, establishing the importance of the outer region in the self-sustaining mechanism of wall bound turbulence.