Large Eddy Simulation of Microbubble Drag Reduction in Fully Developed Turbulent Boundary Layers
Microbubble drag reduction has good application prospects. It operates by injecting a large number of bubbles with tiny diameters into a turbulent boundary layer. However, its mechanism is not yet fully understood. In this paper, the mechanisms of microbubble drag reduction in a fully developed turb...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-07-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/8/7/524 |
| _version_ | 1827712957530767360 |
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| author | Tongsheng Wang Tiezhi Sun Cong Wang Chang Xu Yingjie Wei |
| author_facet | Tongsheng Wang Tiezhi Sun Cong Wang Chang Xu Yingjie Wei |
| author_sort | Tongsheng Wang |
| collection | DOAJ |
| description | Microbubble drag reduction has good application prospects. It operates by injecting a large number of bubbles with tiny diameters into a turbulent boundary layer. However, its mechanism is not yet fully understood. In this paper, the mechanisms of microbubble drag reduction in a fully developed turbulent boundary layer over a flat-plate is investigated using a two-way coupled Euler-Lagrange approach based on large eddy simulation. The results show good agreement with theoretical values in the velocity distribution and the distribution of fluctuation intensities. As the results show, the presence of bubbles reduces the frequency of bursts associated with the sweep events from 637.8 Hz to 611.2 Hz, indicating that the sweep events, namely the impacting of high-speed fluids on the wall surface, are suppressed and the streamwise velocity near the wall is decreased, hence reducing the velocity gradient at the wall and consequently lessening the skin friction. The suppression on burst frequency also, with the fluid fluctuation reduced in degree, decreases the intensity of vortices near the wall, leading to reduced production of turbulent kinetic energy. |
| first_indexed | 2024-03-10T18:26:27Z |
| format | Article |
| id | doaj.art-2c25163c57f44b5fb01723ebfc271df8 |
| institution | Directory Open Access Journal |
| issn | 2077-1312 |
| language | English |
| last_indexed | 2024-03-10T18:26:27Z |
| publishDate | 2020-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Marine Science and Engineering |
| spelling | doaj.art-2c25163c57f44b5fb01723ebfc271df82023-11-20T06:58:16ZengMDPI AGJournal of Marine Science and Engineering2077-13122020-07-018752410.3390/jmse8070524Large Eddy Simulation of Microbubble Drag Reduction in Fully Developed Turbulent Boundary LayersTongsheng Wang0Tiezhi Sun1Cong Wang2Chang Xu3Yingjie Wei4School of Astronautics, Harbin Institute of Technology, Harbin 150001, ChinaSchool of Naval Architecture, Dalian University of Technology, Dalian 116024, ChinaSchool of Astronautics, Harbin Institute of Technology, Harbin 150001, ChinaDepartment of Ocean Engineering, Texas A&M University, College Station, TX 77843, USASchool of Astronautics, Harbin Institute of Technology, Harbin 150001, ChinaMicrobubble drag reduction has good application prospects. It operates by injecting a large number of bubbles with tiny diameters into a turbulent boundary layer. However, its mechanism is not yet fully understood. In this paper, the mechanisms of microbubble drag reduction in a fully developed turbulent boundary layer over a flat-plate is investigated using a two-way coupled Euler-Lagrange approach based on large eddy simulation. The results show good agreement with theoretical values in the velocity distribution and the distribution of fluctuation intensities. As the results show, the presence of bubbles reduces the frequency of bursts associated with the sweep events from 637.8 Hz to 611.2 Hz, indicating that the sweep events, namely the impacting of high-speed fluids on the wall surface, are suppressed and the streamwise velocity near the wall is decreased, hence reducing the velocity gradient at the wall and consequently lessening the skin friction. The suppression on burst frequency also, with the fluid fluctuation reduced in degree, decreases the intensity of vortices near the wall, leading to reduced production of turbulent kinetic energy.https://www.mdpi.com/2077-1312/8/7/524turbulent boundary layermicrobubblesdrag reductionbursts |
| spellingShingle | Tongsheng Wang Tiezhi Sun Cong Wang Chang Xu Yingjie Wei Large Eddy Simulation of Microbubble Drag Reduction in Fully Developed Turbulent Boundary Layers Journal of Marine Science and Engineering turbulent boundary layer microbubbles drag reduction bursts |
| title | Large Eddy Simulation of Microbubble Drag Reduction in Fully Developed Turbulent Boundary Layers |
| title_full | Large Eddy Simulation of Microbubble Drag Reduction in Fully Developed Turbulent Boundary Layers |
| title_fullStr | Large Eddy Simulation of Microbubble Drag Reduction in Fully Developed Turbulent Boundary Layers |
| title_full_unstemmed | Large Eddy Simulation of Microbubble Drag Reduction in Fully Developed Turbulent Boundary Layers |
| title_short | Large Eddy Simulation of Microbubble Drag Reduction in Fully Developed Turbulent Boundary Layers |
| title_sort | large eddy simulation of microbubble drag reduction in fully developed turbulent boundary layers |
| topic | turbulent boundary layer microbubbles drag reduction bursts |
| url | https://www.mdpi.com/2077-1312/8/7/524 |
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