ID | 119362 |
著者 |
Matsudaira, Hayato
The University of Tokushima
Fujimura, Hayato
The University of Tokushima
Ohno, Hideki
The University of Tokushima
|
キーワード | Pipe Flow
Transition
Boundary Layer
Turbulence
Inlet Region
Isolated Turbulent Patch
Propagation Velocity
Turbulent Spot
|
資料タイプ |
学術雑誌論文
|
抄録 | 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.
|
掲載誌名 |
Journal of Fluid Science and Technology
|
ISSN | 18805558
|
出版者 | 日本機械学会
|
巻 | 8
|
号 | 3
|
開始ページ | 436
|
終了ページ | 451
|
発行日 | 2013
|
EDB ID | |
出版社版DOI | |
出版社版URL | |
フルテキストファイル | |
言語 |
eng
|
著者版フラグ |
著者版
|
部局 |
理工学系
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