Direct numerical simulation of a supersonic turbulent boundary layer subject to adverse pressure gradient induced by external successive compression waves
Direct numerical simulation of a supersonic turbulent boundary layer subject to adverse pressure gradient induced by external successive compression waves
A freestream Mach 2.9 flat-plate supersonic turbulent boundary layer subject to a "pure" adverse pressure gradient (APG) without the impact of wall curvatures is studied by direct numerical simulation and compared with a benchmark flow with zero pressure gradient. Due to APG, the streamwise velocity shows an increase in the near-wall region and a reduction in the outer boundary layer. The principal strain rate shows a sandwich distribution along the wall-normal direction. The mismatch between the temperature and velocity fluctuations in both the inner and the outer layer is observed. Enhanced LSMs (large-scale motions) and large velocity patches are the typical flow structures in the outer and inner boundary layer subject to APG, respectively. From the analysis of quadrant decomposition, the sweep events dominate in the near-wall region while ejection events dominate the rest of the boundary layer. It is found that the baroclinicity plays a significant role in the formation of the enhanced LSMs in the outer boundary layer and the near-wall velocity patches. The resulting amplified vorticity further drives the interactive motions of the outer fluid and inner fluid. The turbulent kinetic energy and turbulent Mach number profiles are amplified by APG and a second peak is observed in both profiles. Turbulent energy budget analysis demonstrates that both the production and viscous effects are strengthened in the near-wall region while in the outer layer, the production is significantly amplified and balanced by the increased convection and turbulent transport.
Wang, Xu
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Wang, Zhenguo
19cc9426-43ed-4cda-b150-dfc2e054049c
Sun, Mingbo
2df9eb75-e5d8-48cf-b8e1-00b0b77b3a90
Wang, Qiancheng
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Hu, Zhiwei
dd985844-1e6b-44ba-9e1d-fa57c6c88d65
August 2019
Wang, Xu
aa5b0bc4-7c30-4020-808a-d91d17fb4bc8
Wang, Zhenguo
19cc9426-43ed-4cda-b150-dfc2e054049c
Sun, Mingbo
2df9eb75-e5d8-48cf-b8e1-00b0b77b3a90
Wang, Qiancheng
ed92bab4-2c5d-49a4-918d-c7fb48d90799
Hu, Zhiwei
dd985844-1e6b-44ba-9e1d-fa57c6c88d65
Wang, Xu, Wang, Zhenguo, Sun, Mingbo, Wang, Qiancheng and Hu, Zhiwei
(2019)
Direct numerical simulation of a supersonic turbulent boundary layer subject to adverse pressure gradient induced by external successive compression waves.
AIP Advances, 9 (8), [085215].
(doi:10.1063/1.5112040).
Abstract
A freestream Mach 2.9 flat-plate supersonic turbulent boundary layer subject to a "pure" adverse pressure gradient (APG) without the impact of wall curvatures is studied by direct numerical simulation and compared with a benchmark flow with zero pressure gradient. Due to APG, the streamwise velocity shows an increase in the near-wall region and a reduction in the outer boundary layer. The principal strain rate shows a sandwich distribution along the wall-normal direction. The mismatch between the temperature and velocity fluctuations in both the inner and the outer layer is observed. Enhanced LSMs (large-scale motions) and large velocity patches are the typical flow structures in the outer and inner boundary layer subject to APG, respectively. From the analysis of quadrant decomposition, the sweep events dominate in the near-wall region while ejection events dominate the rest of the boundary layer. It is found that the baroclinicity plays a significant role in the formation of the enhanced LSMs in the outer boundary layer and the near-wall velocity patches. The resulting amplified vorticity further drives the interactive motions of the outer fluid and inner fluid. The turbulent kinetic energy and turbulent Mach number profiles are amplified by APG and a second peak is observed in both profiles. Turbulent energy budget analysis demonstrates that both the production and viscous effects are strengthened in the near-wall region while in the outer layer, the production is significantly amplified and balanced by the increased convection and turbulent transport.
Text
1.5112040
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Accepted/In Press date: 8 August 2019
e-pub ahead of print date: 19 August 2019
Published date: August 2019
Identifiers
Local EPrints ID: 436349
URI: http://eprints.soton.ac.uk/id/eprint/436349
ISSN: 2158-3226
PURE UUID: 3c6119c3-55d4-44df-beb9-df90023ad976
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Date deposited: 06 Dec 2019 17:30
Last modified: 05 Jun 2024 19:59
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Author:
Xu Wang
Author:
Zhenguo Wang
Author:
Mingbo Sun
Author:
Qiancheng Wang
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