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titleOn the concept of hydraulically smooth wall
Other TitleOn the concept of hydraulically smooth wall
Author(jpn)Floryan, J. M.
Author(eng)Floryan, J. M.
Author Affiliation(jpn)University of Western Ontario Department of Mechanical and Materials Engineering
Author Affiliation(eng)University of Western Ontario Department of Mechanical and Materials Engineering
Issue Date2008-02-29
PublisherJapan Aerospace Exploration Agency (JAXA)
宇宙航空研究開発機構
Publication title境界層遷移の解明と制御研究会講演論文集 第40回
Proceedings of the 40th JAXA Workshop on Investigation and Control of Boundary-Layer Transition
Start page17
End page20
Publication date2008-02-29
Languageeng
AbstractA search for a precise definition of hydraulically smooth wall is carried out. It is argued that in the case of transitional flows such definition can be based on the onset of flow instabilities. Flow in a channel with distributed surface roughness is considered as a case study. Results of the linear stability analysis show that the presence of the roughness destabilizes the traveling-wave instability as well as introduces a new instability that manifests itself in the form of streamwise vortices. The critical conditions for the occurrence of both instabilities are given for different classes of roughness shape. It is shown that these conditions can be predicted with a reasonable accuracy in the case of an arbitrary (but Fourier transformable) roughness by considering only the leading Fourier mode (wavy-wall model). A segment in the parameter space where the roughness does not induce any instability regardless of its shape has been identified; this segment identifies conditions under which the rough wall behaves as a hydraulically smooth wall.
DescriptionJAXA Special Publication
宇宙航空研究開発機構特別資料
Keywordssmooth wall; surface roughness; surface roughness effect; transition flow; flow stability; laminar-turbulent transition; traveling wave; equivalent roughness; vortex; Reynolds number; turbulent flow; boundary condition; 平滑壁; 表面粗さ; 粗面効果; 遷移流; 流れの安定性; 層流-乱流遷移; 進行波; 等価粗度; 渦; レイノルズ数; 乱流; 境界条件
Document TypeConference Paper
JAXA Category特別資料
ISSN1349-113X
SHI-NOAA0063908006
Report NoJAXA-SP-07-026E
URIhttps://repository.exst.jaxa.jp/dspace/handle/a-is/29719


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