DC Field | Value | Language |
---|---|---|
dc.contributor.author | Nadeem, Muhammad | ko |
dc.contributor.author | Lee, Jae Hwa | ko |
dc.contributor.author | Lee, Jin | ko |
dc.contributor.author | Sung, Hyung Jin | ko |
dc.date.accessioned | 2016-07-05T07:53:05Z | - |
dc.date.available | 2016-07-05T07:53:05Z | - |
dc.date.created | 2016-01-19 | - |
dc.date.created | 2016-01-19 | - |
dc.date.issued | 2015-12 | - |
dc.identifier.citation | INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW, v.56, pp.16 - 27 | - |
dc.identifier.issn | 0142-727X | - |
dc.identifier.uri | http://hdl.handle.net/10203/209240 | - |
dc.description.abstract | Direct numerical simulations (DNSs) of spatially developing turbulent boundary layers (TBLs) over sparsely-spaced two-dimensional (2D) rod-roughened walls were performed. The rod elements were periodically arranged along the streamwise direction with pitches of p(x)/k = 8, 16, 32, 64 and 128, where p(x) is the streamwise spacing of the rods, and k is the roughness height. The Reynolds number based on the momentum thickness was varied from Re-0 = 300-1400, and the height of the roughness element was k = 1.5 theta(in), where theta(in), is the momentum thickness at the inlet. The characteristics of the TBLs, such as the friction velocity, mean velocity, and Reynolds stresses over the rod-roughened walls, were examined by varying the spacing of the roughness features (8 <= p(x)/k <= 128). The outer-layer similarity between the rough and smooth walls was established for the sparsely-distributed rough walls (p(x)/k >= 32) based on the profiles of the Reynolds stresses, whereas those are not for p(x)/k = 8 and 16. Inspection of the interaction between outer-layer large-scale motions and near-wall small-scale motions using two-point amplitude modulation (AM) covariance showed that modulation effect of large-scale motions on near-wall small-scale motions was strongly disturbed over the rough wall for p(x)/k = 8 and 16. For p(x)/k >= 32, the flow that passed through the upstream roughness element transitioned to a smooth wall flow between the consecutive rods. The strong influence of the surface roughness in the outer layer for p(x)/k = 8 and 16 was attributed to large-scale erupting motions by the surface roughness, creating both upward shift of the near-wall turbulent energy and active energy production in the outer layer with little influence on the near-wall region. | - |
dc.language | English | - |
dc.publisher | ELSEVIER SCIENCE INC | - |
dc.subject | DIRECT NUMERICAL-SIMULATION | - |
dc.subject | SURFACE-ROUGHNESS | - |
dc.subject | CHANNEL FLOW | - |
dc.subject | SIMILARITY | - |
dc.subject | MECHANISMS | - |
dc.subject | SMOOTH | - |
dc.title | Turbulent boundary layers over sparsely-spaced rod-roughened walls | - |
dc.type | Article | - |
dc.identifier.wosid | 000366961900002 | - |
dc.identifier.scopusid | 2-s2.0-84937573051 | - |
dc.type.rims | ART | - |
dc.citation.volume | 56 | - |
dc.citation.beginningpage | 16 | - |
dc.citation.endingpage | 27 | - |
dc.citation.publicationname | INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW | - |
dc.identifier.doi | 10.1016/j.ijheatfluidflow.2015.06.006 | - |
dc.contributor.localauthor | Sung, Hyung Jin | - |
dc.type.journalArticle | Article | - |
dc.subject.keywordAuthor | Direct numerical simulation | - |
dc.subject.keywordAuthor | Turbulent boundary layers | - |
dc.subject.keywordAuthor | Roughness | - |
dc.subject.keywordAuthor | Amplitude modulation | - |
dc.subject.keywordPlus | DIRECT NUMERICAL-SIMULATION | - |
dc.subject.keywordPlus | SURFACE-ROUGHNESS | - |
dc.subject.keywordPlus | CHANNEL FLOW | - |
dc.subject.keywordPlus | SIMILARITY | - |
dc.subject.keywordPlus | MECHANISMS | - |
dc.subject.keywordPlus | SMOOTH | - |
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