Drag reduction in spatially developing turbulent boundary layers by spatially intermittent blowing at constant mass-flux

Yukinori Kametani, Koji Fukagata, Ramis Örlü, Philipp Schlatter

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

A series of large-eddy simulations of spatially developing turbulent boundary layers with uniform blowing at moderate Reynolds numbers (based on free-stream velocity, U, and momentum thickness, θ) up to Reθ ≈ 2500 were performed with the special focus on the effect of intermittent (separated in streamwise direction) blowing sections. The number of blowing sections, N, investigated is set to be 3, 6, 20, 30 and compared to N = 1, which constitutes the reference case, while the total wall-mass flux is constrained to be the same for all considered cases, corresponding to a blowing amplitude of 0.1% of U for the reference case. Results indicate that the reference case provides a net-energy saving rate of around 18%, which initially decreases at most 2% points for N = 3 but recovers with increasing N, where the initial reduction of the drag reduction is found to be related to the shorter streamwise length of the intermittent blowing sections. The physical decomposition of the skin friction drag through the Fukagata-Iwamoto-Kasagi (FIK) identity shows that the distribution of all components over each blowing section has similar trends, resulting in similar averaged values over the whole control region.

Original languageEnglish
Pages (from-to)913-929
Number of pages17
JournalJournal of Turbulence
Volume17
Issue number10
DOIs
Publication statusPublished - 2016 Oct 2

Keywords

  • Turbulent boundary layer
  • blowing
  • flow control

ASJC Scopus subject areas

  • Computational Mechanics
  • Condensed Matter Physics
  • Mechanics of Materials
  • Physics and Astronomy(all)

Fingerprint Dive into the research topics of 'Drag reduction in spatially developing turbulent boundary layers by spatially intermittent blowing at constant mass-flux'. Together they form a unique fingerprint.

  • Cite this