Opposition control of turbulent spots

Y. X. Wang, K. S. Choi, M. Gaster, C. Atkin, V. Borodulin, Y. Kachanov

Research output: Contribution to journalArticlepeer-review

Abstract

Opposition control of artificially initiated turbulent spots in a laminar boundary layer was carried out in a low-turbulence wind tunnel with the aim to delay transition to turbulence by modifying the turbulent structure within the turbulent spots. The timing and duration of control, which was carried out using wall-normal jets from a spanwise slot, were pre-determined based on the baseline measurements of the transitional boundary layer. The results indicated that the high-speed region of the turbulent spots was cancelled by opposition control, which was replaced by a carpet of low-speed fluid. The application of the variable-interval time-averaging technique on the velocity fluctuation signals demonstrated a reduction in both the burst duration and intensity within the turbulent spots, but the burst frequency was increased.

Original languageEnglish
Article numberA3
JournalJournal of Fluid Mechanics
Volume943
Early online date6 Jun 2022
DOIs
Publication statusPublished - 25 Jul 2022

Keywords

  • boundary layer control
  • drag reduction
  • transition to turbulence

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