Distinct large-scale turbulent-laminar states in transitional pipe flow
Moxey, David C. and Barkley, Dwight. (2010) Distinct large-scale turbulent-laminar states in transitional pipe flow. Proceedings of the National Academy of Sciences of the United States of America, Vol.107 (No.18). pp. 8091-8096. ISSN 0027-8424Full text not available from this repository.
Official URL: http://dx.doi.org/10.1073/pnas.0909560107
When fluid flows through a channel, pipe, or duct, there are two basic forms of motion: smooth laminar motion and complex turbulent motion. The discontinuous transition between these states is a fundamental problem that has been studied for more than 100 yr. What has received far less attention is the large-scale nature of the turbulent flows near transition once they are established. We have carried out extensive numerical computations in pipes of variable lengths up to 125 diameters to investigate the nature of transitional turbulence in pipe flow. We show the existence of three fundamentally different turbulent states separated by two distinct Reynolds numbers. Below Re-1 similar or equal to 2,300, turbulence takes the form of familiar equilibrium ( or longtime transient) puffs that are spatially localized and keep their size independent of pipe length. At Re-1 the flow makes a striking transition to a spatio-temporally intermittent flow that fills the pipe. Irregular alternation of turbulent and laminar regions is inherent and does not result from random disturbances. The fraction of turbulence increases with Re until Re-2 similar or equal to 2,600 where there is a continuous transition to a state of uniform turbulence along the pipe. We relate these observations to directed percolation and argue that Re-1 marks the onset of infinite-lifetime turbulence.
|Item Type:||Journal Article|
|Divisions:||Faculty of Science > Mathematics|
|Journal or Publication Title:||Proceedings of the National Academy of Sciences of the United States of America|
|Publisher:||National Academy of Sciences|
|Official Date:||4 May 2010|
|Number of Pages:||6|
|Page Range:||pp. 8091-8096|
|Access rights to Published version:||Restricted or Subscription Access|
|Funder:||Royal Society (Great Britain), Engineering and Physical Sciences Research Council (EPSRC), Grand Equipement National de Calcul Intensif-Institut du Developpement et des Ressources en Informatique Scientifique, Leverhulme Trust (LT)|
|Grant number:||2009-1119, 2010-1119|
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