Prediction of drag reduction effect by streamwise traveling wave-like wall deformation in turbulent channel flow at practically high Reynolds numbers

Yusuke Nabae, Ken Kawai, Koji Fukagata

Research output: Contribution to journalArticle

Abstract

A fully developed turbulent channel flow controlled by traveling wave-like wall deformation under a constant pressure gradient condition is studied numerically and theoretically. First, direct numerical simulation (DNS) at three different friction Reynolds numbers, Reτ=90, 180, and 360, are performed to investigate the modification in turbulence statistics and their scaling. Unlike the previous study assuming a constant flow rate condition, suppression of the quasi-streamwise vortices is not observed in either drag decrease cases or drag increase cases. It is found in the drag reduction case, however, that the periodic component of the Reynolds shear stress (periodic RSS) is largely negative in the viscous sublayer and the buffer layer. For the maximum drag reduction case, the set of control parameters is found to be identical in wall units regardless of the Reynolds number, and the resulting mean velocity profiles are also observed to be approximately similar even with an additional case of Reτ=720. Based on this scaling, we propose a semi-empirical formula for the mean velocity profile modified by the present control. With this formula, about 20%−25% drag reduction effect is predicted even at practically high Reynolds numbers, Reτ∼105−106.

Original languageEnglish
Article number108550
JournalInternational Journal of Heat and Fluid Flow
Volume82
DOIs
Publication statusPublished - 2020 Apr

Keywords

  • Drag reduction
  • High Reynolds number
  • Theoretical prediction
  • Turbulent channel flow
  • Wall deformation

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

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