Numerical and experimental investigations on drag-reducing effects of riblets

The numerical simulation and force measurement experiment are conducted in this work. The direct numerical simulation method with high-order schemes is performed to resolve the incompressible turbulent flow over riblets. According to the turbulent statistics, behaviors of the large-scale streamwise...

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Autores principales: Chaoqun Li, Shuo Tang, Yi Li, Zihai Geng
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Lenguaje:EN
Publicado: Taylor & Francis Group 2021
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Acceso en línea:https://doaj.org/article/5a723d0169e5422e92ff9634243e34fd
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spelling oai:doaj.org-article:5a723d0169e5422e92ff9634243e34fd2021-11-04T15:00:43ZNumerical and experimental investigations on drag-reducing effects of riblets1994-20601997-003X10.1080/19942060.2021.1989043https://doaj.org/article/5a723d0169e5422e92ff9634243e34fd2021-01-01T00:00:00Zhttp://dx.doi.org/10.1080/19942060.2021.1989043https://doaj.org/toc/1994-2060https://doaj.org/toc/1997-003XThe numerical simulation and force measurement experiment are conducted in this work. The direct numerical simulation method with high-order schemes is performed to resolve the incompressible turbulent flow over riblets. According to the turbulent statistics, behaviors of the large-scale streamwise vortices above riblets are analyzed. In drag-reducing cases, the population density of streamwise vortices near the wall decreases, and the ratio of contributions of the large-scale streamwise vortices to the total mean shear is also lowered. In addition, streamwise vortices are situated near riblet tips, and spanwise motions of the vortices are weakened. Consequently, they are anchored at the riblet surface. In the experimental investigation, the drag characteristics of a transport aircraft mounted with riblets are studied in a low-speed wind tunnel. The angle of attack (AoA) ranges between −2 $ ^{\circ } $ and 20 $ ^{\circ } $ , and the test speed is up to 70 m/s. A maximum of nearly 40% decline in drag coefficient is achieved at 10 $ ^{\circ } $ AoA. Because the riblet surface makes the fluid more irrotational and the vortices are anchored at the wall, the flow separation is weakened at moderate AoAs, which indicates that the pressure drag is also reduced in the circumstance.Chaoqun LiShuo TangYi LiZihai GengTaylor & Francis Grouparticleflow controlribletsdirect numerical simulationhigh-order schemeswind tunnel experimentsEngineering (General). Civil engineering (General)TA1-2040ENEngineering Applications of Computational Fluid Mechanics, Vol 15, Iss 1, Pp 1726-1745 (2021)
institution DOAJ
collection DOAJ
language EN
topic flow control
riblets
direct numerical simulation
high-order schemes
wind tunnel experiments
Engineering (General). Civil engineering (General)
TA1-2040
spellingShingle flow control
riblets
direct numerical simulation
high-order schemes
wind tunnel experiments
Engineering (General). Civil engineering (General)
TA1-2040
Chaoqun Li
Shuo Tang
Yi Li
Zihai Geng
Numerical and experimental investigations on drag-reducing effects of riblets
description The numerical simulation and force measurement experiment are conducted in this work. The direct numerical simulation method with high-order schemes is performed to resolve the incompressible turbulent flow over riblets. According to the turbulent statistics, behaviors of the large-scale streamwise vortices above riblets are analyzed. In drag-reducing cases, the population density of streamwise vortices near the wall decreases, and the ratio of contributions of the large-scale streamwise vortices to the total mean shear is also lowered. In addition, streamwise vortices are situated near riblet tips, and spanwise motions of the vortices are weakened. Consequently, they are anchored at the riblet surface. In the experimental investigation, the drag characteristics of a transport aircraft mounted with riblets are studied in a low-speed wind tunnel. The angle of attack (AoA) ranges between −2 $ ^{\circ } $ and 20 $ ^{\circ } $ , and the test speed is up to 70 m/s. A maximum of nearly 40% decline in drag coefficient is achieved at 10 $ ^{\circ } $ AoA. Because the riblet surface makes the fluid more irrotational and the vortices are anchored at the wall, the flow separation is weakened at moderate AoAs, which indicates that the pressure drag is also reduced in the circumstance.
format article
author Chaoqun Li
Shuo Tang
Yi Li
Zihai Geng
author_facet Chaoqun Li
Shuo Tang
Yi Li
Zihai Geng
author_sort Chaoqun Li
title Numerical and experimental investigations on drag-reducing effects of riblets
title_short Numerical and experimental investigations on drag-reducing effects of riblets
title_full Numerical and experimental investigations on drag-reducing effects of riblets
title_fullStr Numerical and experimental investigations on drag-reducing effects of riblets
title_full_unstemmed Numerical and experimental investigations on drag-reducing effects of riblets
title_sort numerical and experimental investigations on drag-reducing effects of riblets
publisher Taylor & Francis Group
publishDate 2021
url https://doaj.org/article/5a723d0169e5422e92ff9634243e34fd
work_keys_str_mv AT chaoqunli numericalandexperimentalinvestigationsondragreducingeffectsofriblets
AT shuotang numericalandexperimentalinvestigationsondragreducingeffectsofriblets
AT yili numericalandexperimentalinvestigationsondragreducingeffectsofriblets
AT zihaigeng numericalandexperimentalinvestigationsondragreducingeffectsofriblets
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