Viscoelastic effect on steady wavy roll cells in wall-bounded shear flow

Tomohiro Nimura, Takuya Kawata, Takahiro Tsukahara

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

An alternative step in understanding the flows of near wall drag-reducing turbulence can be examining the flow in a well-organized streamwise vortex with a laminar background. Herein, we studied the flow behaviors of the Giesekus viscoelastic fluid in a rotating plane Couette flow system, which is accompanied by steady roll cell structures. By fixing the Reynolds and rotation numbers at values that provide as steady wavy roll cell, i.e., an array of meandering streamwise vortices, the Weissenberg number was increased up to 2000 (where the relaxation time was normalized by the wall speed and the kinematic viscosity). We observed that, in the viscoelastic flows, the secondary flow (wall-normal and spanwise velocity fluctuations) are suppressed while the streamwise component is maintained, and the wavy roll cells are modulated into streamwise-independent straight roll cells. The kinetic energy transports among the mean shear flow, Reynolds stresses due to the roll cell, and viscoelastic stress are investigated in the non-turbulent background. We further discussed the modulation mechanism and its relevance to the drag reduction phenomenon in the viscoelastic wall turbulence.

Original languageEnglish
Article number051414
JournalFluid Dynamics Research
Volume50
Issue number5
DOIs
Publication statusPublished - 2018 Aug 23
Externally publishedYes

Keywords

  • DNS
  • drag reduction
  • rotating plane Couette flow
  • viscoelastic fluid

ASJC Scopus subject areas

  • Mechanical Engineering
  • Physics and Astronomy(all)
  • Fluid Flow and Transfer Processes

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