Laminar-Turbulent Transition of an Inlet Boundary Layer in a Circular Pipe Induced by Periodic Injection (Shape of Isolated Turbulent Patches and Their Growth)
The laminar-turbulent transition of a boundary layer induced by a jet injection in the inlet region of a circular pipe was experimentally investigated. The jet was periodically injected radially from a small hole in the inlet region into the pipe flow. Axial velocity was measured by a hot-wire anemo...
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| Format: | Article |
| Language: | English |
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The Japan Society of Mechanical Engineers
2013-12-01
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| Series: | Journal of Fluid Science and Technology |
| Subjects: | |
| Online Access: | https://www.jstage.jst.go.jp/article/jfst/8/3/8_436/_pdf/-char/en |
| _version_ | 1818753730359590912 |
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| author | Masashi ICHIMIYA Hayato MATSUDAIRA Hayato FUJIMURA Hideki OHNO |
| author_facet | Masashi ICHIMIYA Hayato MATSUDAIRA Hayato FUJIMURA Hideki OHNO |
| author_sort | Masashi ICHIMIYA |
| collection | DOAJ |
| description | The laminar-turbulent transition of a boundary layer induced by a jet injection in the inlet region of a circular pipe was experimentally investigated. The jet was periodically injected radially from a small hole in the inlet region into the pipe flow. Axial velocity was measured by a hot-wire anemometer. The turbulence induced by the jet within the boundary layer developed into turbulent patches which then grew in the axial, circumferential and radial directions downstream. The shape of the patches shown by the intermittency factor in the diametrical plane was similar to the turbulent spot in the flat plate boundary layer at first, then became similar to the turbulent slug in the pipe flow developed downstream. The turbulent patches protruded from the boundary layer after they grew and reached the circumferential opposite side, although they stayed within the boundary layer as long as the shape was turbulent spot-like in the diametrical plane. The propagation velocity at the leading edge became faster than the cross-sectional velocity, though it turned slower at the trailing edge. Therefore, the growth rate of its axial length varied downstream. The growth rate of the patches' circumferential length was smaller than that in the turbulent spot under zero pressure gradient and was almost the same as the spot under favorable pressure gradient. |
| first_indexed | 2024-12-18T05:12:00Z |
| format | Article |
| id | doaj.art-b965c19d566b43399b5cbff0a77befe2 |
| institution | Directory Open Access Journal |
| issn | 1880-5558 |
| language | English |
| last_indexed | 2024-12-18T05:12:00Z |
| publishDate | 2013-12-01 |
| publisher | The Japan Society of Mechanical Engineers |
| record_format | Article |
| series | Journal of Fluid Science and Technology |
| spelling | doaj.art-b965c19d566b43399b5cbff0a77befe22022-12-21T21:19:53ZengThe Japan Society of Mechanical EngineersJournal of Fluid Science and Technology1880-55582013-12-018343645110.1299/jfst.8.436jfstLaminar-Turbulent Transition of an Inlet Boundary Layer in a Circular Pipe Induced by Periodic Injection (Shape of Isolated Turbulent Patches and Their Growth)Masashi ICHIMIYA0Hayato MATSUDAIRA1Hayato FUJIMURA2Hideki OHNO3Institute of Technology and Science, The University of TokushimaGraduate School, The University of TokushimaGraduate School, The University of TokushimaGraduate School, The University of TokushimaThe laminar-turbulent transition of a boundary layer induced by a jet injection in the inlet region of a circular pipe was experimentally investigated. The jet was periodically injected radially from a small hole in the inlet region into the pipe flow. Axial velocity was measured by a hot-wire anemometer. The turbulence induced by the jet within the boundary layer developed into turbulent patches which then grew in the axial, circumferential and radial directions downstream. The shape of the patches shown by the intermittency factor in the diametrical plane was similar to the turbulent spot in the flat plate boundary layer at first, then became similar to the turbulent slug in the pipe flow developed downstream. The turbulent patches protruded from the boundary layer after they grew and reached the circumferential opposite side, although they stayed within the boundary layer as long as the shape was turbulent spot-like in the diametrical plane. The propagation velocity at the leading edge became faster than the cross-sectional velocity, though it turned slower at the trailing edge. Therefore, the growth rate of its axial length varied downstream. The growth rate of the patches' circumferential length was smaller than that in the turbulent spot under zero pressure gradient and was almost the same as the spot under favorable pressure gradient.https://www.jstage.jst.go.jp/article/jfst/8/3/8_436/_pdf/-char/enpipe flowtransitionboundary layerturbulenceinlet regionisolated turbulent patchpropagation velocityturbulent spot |
| spellingShingle | Masashi ICHIMIYA Hayato MATSUDAIRA Hayato FUJIMURA Hideki OHNO Laminar-Turbulent Transition of an Inlet Boundary Layer in a Circular Pipe Induced by Periodic Injection (Shape of Isolated Turbulent Patches and Their Growth) Journal of Fluid Science and Technology pipe flow transition boundary layer turbulence inlet region isolated turbulent patch propagation velocity turbulent spot |
| title | Laminar-Turbulent Transition of an Inlet Boundary Layer in a Circular Pipe Induced by Periodic Injection (Shape of Isolated Turbulent Patches and Their Growth) |
| title_full | Laminar-Turbulent Transition of an Inlet Boundary Layer in a Circular Pipe Induced by Periodic Injection (Shape of Isolated Turbulent Patches and Their Growth) |
| title_fullStr | Laminar-Turbulent Transition of an Inlet Boundary Layer in a Circular Pipe Induced by Periodic Injection (Shape of Isolated Turbulent Patches and Their Growth) |
| title_full_unstemmed | Laminar-Turbulent Transition of an Inlet Boundary Layer in a Circular Pipe Induced by Periodic Injection (Shape of Isolated Turbulent Patches and Their Growth) |
| title_short | Laminar-Turbulent Transition of an Inlet Boundary Layer in a Circular Pipe Induced by Periodic Injection (Shape of Isolated Turbulent Patches and Their Growth) |
| title_sort | laminar turbulent transition of an inlet boundary layer in a circular pipe induced by periodic injection shape of isolated turbulent patches and their growth |
| topic | pipe flow transition boundary layer turbulence inlet region isolated turbulent patch propagation velocity turbulent spot |
| url | https://www.jstage.jst.go.jp/article/jfst/8/3/8_436/_pdf/-char/en |
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