Opposition control of turbulent spots

Wang, Y. X., Choi, K. S., Gaster, M., Atkin, C. ORCID: https://orcid.org/0000-0003-2529-1978, Borodulin, V. and Kachanov, Y. (2022) Opposition control of turbulent spots. Journal of Fluid Mechanics, 943. ISSN 0022-1120

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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.

Item Type: Article
Additional Information: Funding Information: This work was supported by EPSRC grant EP/M028690/1.
Uncontrolled Keywords: boundary layer control,drag reduction,transition to turbulence,condensed matter physics,mechanics of materials,mechanical engineering,applied mathematics ,/dk/atira/pure/subjectarea/asjc/3100/3104
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Depositing User: LivePure Connector
Date Deposited: 20 Jul 2022 12:30
Last Modified: 12 Aug 2022 06:43
URI: https://ueaeprints.uea.ac.uk/id/eprint/86729
DOI: 10.1017/jfm.2022.396

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