Streamwise Interfaces of an Isolated Turbulent Region in a Laminar Boundary Layer
The streamwise interfaces of an isolated turbulent region in a flat plate boundary layer are investigated by performing a wind tunnel experiment. A bimorph-type piezoceramic actuator is used to generate a trapezoidal turbulent region whose spanwise width is larger than those of a typical turbulent s...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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The Japan Society of Mechanical Engineers
2012-06-01
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| Series: | Journal of Fluid Science and Technology |
| Subjects: | |
| Online Access: | https://www.jstage.jst.go.jp/article/jfst/7/1/7_140/_pdf/-char/en |
| _version_ | 1818753720131780608 |
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| author | Osamu TERASHIMA Seiichiro IZAWA Ayumu INASAWA Yu FUKUNISHI |
| author_facet | Osamu TERASHIMA Seiichiro IZAWA Ayumu INASAWA Yu FUKUNISHI |
| author_sort | Osamu TERASHIMA |
| collection | DOAJ |
| description | The streamwise interfaces of an isolated turbulent region in a flat plate boundary layer are investigated by performing a wind tunnel experiment. A bimorph-type piezoceramic actuator is used to generate a trapezoidal turbulent region whose spanwise width is larger than those of a typical turbulent spot. The experimental results show that the traveling speeds of the leading and trailing ends of the turbulent region are almost same as those of the turbulent spots with an arrow-head shape. This result indicate that the spanwise width have little influence to the streamwise growth of an isolated turbulent region. It is also found that the traveling speed of the trailing end of the turbulent region exceeds that of local flow velocity in the near-wall region, which is η < 1.3, and vice versa. This result shows that a relaminarization is in progress in the near-wall region, where the turbulent fluid is moving across the trailing end turning laminar. The critical wall-normal distance of η = 1.3 corresponds to about 10 in the wall unit (y+), suggesting that the relaminarization process is taking place in the viscous sublayer. |
| first_indexed | 2024-12-18T05:11:50Z |
| format | Article |
| id | doaj.art-a13e5c8767c5424985d49585d157ecaa |
| institution | Directory Open Access Journal |
| issn | 1880-5558 |
| language | English |
| last_indexed | 2024-12-18T05:11:50Z |
| publishDate | 2012-06-01 |
| publisher | The Japan Society of Mechanical Engineers |
| record_format | Article |
| series | Journal of Fluid Science and Technology |
| spelling | doaj.art-a13e5c8767c5424985d49585d157ecaa2022-12-21T21:19:53ZengThe Japan Society of Mechanical EngineersJournal of Fluid Science and Technology1880-55582012-06-017114015410.1299/jfst.7.140jfstStreamwise Interfaces of an Isolated Turbulent Region in a Laminar Boundary LayerOsamu TERASHIMA0Seiichiro IZAWA1Ayumu INASAWA2Yu FUKUNISHI3Department of Mechanical Science and Engineering, Nagoya UniversityDepartment of Mechanical Systems and Design, Tohoku UniversityDepartment of Aerospace Engineering, Tokyo Metropolitan UniversityDepartment of Mechanical Systems and Design, Tohoku UniversityThe streamwise interfaces of an isolated turbulent region in a flat plate boundary layer are investigated by performing a wind tunnel experiment. A bimorph-type piezoceramic actuator is used to generate a trapezoidal turbulent region whose spanwise width is larger than those of a typical turbulent spot. The experimental results show that the traveling speeds of the leading and trailing ends of the turbulent region are almost same as those of the turbulent spots with an arrow-head shape. This result indicate that the spanwise width have little influence to the streamwise growth of an isolated turbulent region. It is also found that the traveling speed of the trailing end of the turbulent region exceeds that of local flow velocity in the near-wall region, which is η < 1.3, and vice versa. This result shows that a relaminarization is in progress in the near-wall region, where the turbulent fluid is moving across the trailing end turning laminar. The critical wall-normal distance of η = 1.3 corresponds to about 10 in the wall unit (y+), suggesting that the relaminarization process is taking place in the viscous sublayer.https://www.jstage.jst.go.jp/article/jfst/7/1/7_140/_pdf/-char/enboundary layerlaminar-turbulent interfaceisolated turbulent region |
| spellingShingle | Osamu TERASHIMA Seiichiro IZAWA Ayumu INASAWA Yu FUKUNISHI Streamwise Interfaces of an Isolated Turbulent Region in a Laminar Boundary Layer Journal of Fluid Science and Technology boundary layer laminar-turbulent interface isolated turbulent region |
| title | Streamwise Interfaces of an Isolated Turbulent Region in a Laminar Boundary Layer |
| title_full | Streamwise Interfaces of an Isolated Turbulent Region in a Laminar Boundary Layer |
| title_fullStr | Streamwise Interfaces of an Isolated Turbulent Region in a Laminar Boundary Layer |
| title_full_unstemmed | Streamwise Interfaces of an Isolated Turbulent Region in a Laminar Boundary Layer |
| title_short | Streamwise Interfaces of an Isolated Turbulent Region in a Laminar Boundary Layer |
| title_sort | streamwise interfaces of an isolated turbulent region in a laminar boundary layer |
| topic | boundary layer laminar-turbulent interface isolated turbulent region |
| url | https://www.jstage.jst.go.jp/article/jfst/7/1/7_140/_pdf/-char/en |
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