Reference : On the mechanism of elasto-inertial turbulence
Scientific journals : Article
Engineering, computing & technology : Chemical engineering
Engineering, computing & technology : Mechanical engineering
http://hdl.handle.net/2268/154268
On the mechanism of elasto-inertial turbulence
English
Dubief, Yves [University of Vermont > > > >]
Soria, Julio []
Terrapon, Vincent mailto [Université de Liège - ULiège > Département d'aérospatiale et mécanique > Modélisation et contrôle des écoulements turbulents >]
Nov-2013
Physics of Fluids
American Institute of Physics
25
110817
Special Topic: Directions In Computational Physics
1-16
Yes (verified by ORBi)
International
1070-6631
1089-7666
Melville
NY
[en] Elasto-inertial Turbulence ; Polymer ; Drag reduction ; DNS ; Channel flow ; FENE-P
[en] Elasto-inertial turbulence (EIT) is a new state of turbulence found in inertial flows with polymer additives. The dynamics of turbulence generated and controlled by such additives is investigated from the perspective of the coupling between polymer dynamics and flow structures. Direct numerical simulations of channel flow with Reynolds numbers ranging from 1000 to 6000 (based on the bulk and the channel height) are used to study the formation and dynamics of elastic instabilities and their effects on the flow. The flow topology of EIT is found to differ significantly from Newtonian wall-turbulence. Structures identified by positive (rotational flow topology) and negative (extensional/compressional flow topology) second invariant Qa isosurfaces of the velocity gradient are cylindrical and aligned in the spanwise direction. Polymers are significantly stretched in sheet-like regions that extend in the streamwise direction with a small upward tilt. The Qa cylindrical structures emerge from the sheets of high polymer extension, in a mechanism of energy transfer from the fluctuations of the polymer stress work to the turbulent kinetic energy. At subcritical Reynolds numbers, EIT is observed at modest Weissenberg number (Wi, ratio polymer relaxation time to viscous time scale). For supercritical Reynolds numbers, flows approach EIT at large Wi. EIT provides new insights on the nature of the asymptotic state of polymer drag reduction (maximum drag reduction), and explains the phenomenon of early turbulence, or onset of turbulence at lower Reynolds numbers than for Newtonian flows observed in some polymeric flows.
Researchers ; Professionals ; Students ; Others
http://hdl.handle.net/2268/154268
10.1063/1.4820142
http://dx.doi.org/10.1063/1.4820142
Copyright 2013 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
The following article appeared in Phys. Fluids 25, 110817 (2013), and may be found at http://dx.doi.org/10.1063/1.4820142.
FP7 ; 304073 - VISCELTURBFLOW - Computational study of macro- and microscopic turbulence controlled by polymer additives

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