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Color-coded visualization of microbubble clouds interacting with eddies in a spatially developing turbulent boundary layer
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| Title: | Color-coded visualization of microbubble clouds interacting with eddies in a spatially developing turbulent boundary layer |
| Authors: | Park, Hyun Jin Browse this author | | Saito, Daichi Browse this author | | Tasaka, Yuji Browse this author →KAKEN DB | | Murai, Yuichi Browse this author →KAKEN DB |
| Keywords: | Drag reduction | | Microbubbles | | Turbulent boundary layer | | Flow visualization |
| Issue Date: | Dec-2019 |
| Publisher: | Elsevier |
| Journal Title: | Experimental thermal and fluid science |
| Volume: | 109 |
| Start Page: | UNSP 109919 |
| Publisher DOI: | 10.1016/j.expthermflusci.2019.109919 |
| Abstract: | Three-dimensional distribution of microbubbles dispersed in a turbulent boundary layer spatially developing along a flat plate is investigated experimentally. The aim of study is to find out visually how microbubbles interact with turbulent eddies to achieve frictional drag reduction on a wall. Setting conditions of the experiments are stream Reynolds number up to 2.3 x 10(4), microbubble volume fraction inside boundary layer less than 10(-5), and microbubble Stokes number smaller than 10(-3). Stream-wise vortices in the boundary layer were visualized by flake optics, of which spacing expands with injection of microbubbles. 3-D microbubble distributions were visualized by a color-coded volumetric illumination. The result showed preferentially accumulated microbubble clouds to low-speed streaks close to viscous sublayer and to hair-pin vortices in the buffer layer, leading to reduced diffusivity of microbubbles relative to the turbulent momentum diffusivity. |
| Rights: | © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ | | http://creativecommons.org/licenses/by-nc-nd/4.0/ |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/83367 |
| Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 朴 炫珍
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