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Media type:
E-Article
Title:
Control of laminar breakdown in a supersonic boundary layer employing streaks
Contributor:
Kneer, Simon;
Guo, Zhengfei;
Kloker, Markus J.
Published:
Cambridge University Press (CUP), 2022
Published in:
Journal of Fluid Mechanics, 932 (2022)
Language:
English
DOI:
10.1017/jfm.2021.1047
ISSN:
0022-1120;
1469-7645
Origination:
Footnote:
Description:
In this study direct numerical simulations are employed to investigate the effects of various parameters on the laminar-flow-control capabilities of narrowly spaced streaks in a supersonic boundary layer at Mach$2.0$. Previous work by Sharmaet al.(J. Fluid Mech., vol. 873, 2019, pp. 1072–1089) has found these streak modes, excited by a spanwise blowing-and-suction strip, to be highly effective at delaying pure oblique-type breakdown. In the present work it is shown that spectrum-enriching subharmonic modes, relevant with increasing running-length Reynolds number, do not destroy the controlling mechanism, and also a complex breakdown scenario, triggered by a multi-frequency point source, is found to be effectively controlled. Moreover, the control-streak excitation by roughness elements is compared in detail with the blowing-and-suction method, revealing relevant differing features.