Influence of Synthetic Jets on Multiscale Features in Wall-Bounded Turbulence
This experimental research focuses on the impacts of submerged synthetic jets on a fully-developed turbulent boundary layer (TBL) under a drag reduction working case. Two-dimensional velocity vectors in the flow field are captured with the aid of a particle image velocimetry (PIV) system. Proper ort...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-07-01
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| Series: | Actuators |
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| Online Access: | https://www.mdpi.com/2076-0825/11/7/199 |
| _version_ | 1797434004780089344 |
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| author | Biaohui Li Jinhao Zhang Nan Jiang |
| author_facet | Biaohui Li Jinhao Zhang Nan Jiang |
| author_sort | Biaohui Li |
| collection | DOAJ |
| description | This experimental research focuses on the impacts of submerged synthetic jets on a fully-developed turbulent boundary layer (TBL) under a drag reduction working case. Two-dimensional velocity vectors in the flow field are captured with the aid of a particle image velocimetry (PIV) system. Proper orthogonal decomposition (POD) analyses provide evidence that synthetic jets notably attenuate the induction effect of prograde vortex on the low-speed fluid in large-scale fluctuation velocity field, thereby weakening the bursting process of near-wall turbulent events. Furthermore, the introduced perturbance redistributes the turbulent kinetic energy (TKE) and concentrates the TKE onto small-scale coherent structures. Modal time coefficients in various orders of POD are divided into components of multiple frequency bands by virtue of complementary ensemble empirical mode decomposition (CEEMD). It is found that the turbulence signals are shifted from low-frequency to high-frequency bands thanks to synthetic jets, thus revealing the relationship between scales and frequency bands. One further method of scale decomposition is proposed, that is, the large-scale fluctuating flow field will be obtained after removing the high-frequency noise data with the help of continuous mean square error (CMSE) criterion. |
| first_indexed | 2024-03-09T10:23:58Z |
| format | Article |
| id | doaj.art-3eec841674af43949368c376c8850c51 |
| institution | Directory Open Access Journal |
| issn | 2076-0825 |
| language | English |
| last_indexed | 2024-03-09T10:23:58Z |
| publishDate | 2022-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Actuators |
| spelling | doaj.art-3eec841674af43949368c376c8850c512023-12-01T21:45:10ZengMDPI AGActuators2076-08252022-07-0111719910.3390/act11070199Influence of Synthetic Jets on Multiscale Features in Wall-Bounded TurbulenceBiaohui Li0Jinhao Zhang1Nan Jiang2School of Mechanical Engineering, Tianjin University, 135 Yaguan Road, Tianjin 300350, ChinaSchool of Mechanical Engineering, Tianjin University, 135 Yaguan Road, Tianjin 300350, ChinaSchool of Mechanical Engineering, Tianjin University, 135 Yaguan Road, Tianjin 300350, ChinaThis experimental research focuses on the impacts of submerged synthetic jets on a fully-developed turbulent boundary layer (TBL) under a drag reduction working case. Two-dimensional velocity vectors in the flow field are captured with the aid of a particle image velocimetry (PIV) system. Proper orthogonal decomposition (POD) analyses provide evidence that synthetic jets notably attenuate the induction effect of prograde vortex on the low-speed fluid in large-scale fluctuation velocity field, thereby weakening the bursting process of near-wall turbulent events. Furthermore, the introduced perturbance redistributes the turbulent kinetic energy (TKE) and concentrates the TKE onto small-scale coherent structures. Modal time coefficients in various orders of POD are divided into components of multiple frequency bands by virtue of complementary ensemble empirical mode decomposition (CEEMD). It is found that the turbulence signals are shifted from low-frequency to high-frequency bands thanks to synthetic jets, thus revealing the relationship between scales and frequency bands. One further method of scale decomposition is proposed, that is, the large-scale fluctuating flow field will be obtained after removing the high-frequency noise data with the help of continuous mean square error (CMSE) criterion.https://www.mdpi.com/2076-0825/11/7/199active controlmultiscalesynthetic jetturbulent boundary layer |
| spellingShingle | Biaohui Li Jinhao Zhang Nan Jiang Influence of Synthetic Jets on Multiscale Features in Wall-Bounded Turbulence Actuators active control multiscale synthetic jet turbulent boundary layer |
| title | Influence of Synthetic Jets on Multiscale Features in Wall-Bounded Turbulence |
| title_full | Influence of Synthetic Jets on Multiscale Features in Wall-Bounded Turbulence |
| title_fullStr | Influence of Synthetic Jets on Multiscale Features in Wall-Bounded Turbulence |
| title_full_unstemmed | Influence of Synthetic Jets on Multiscale Features in Wall-Bounded Turbulence |
| title_short | Influence of Synthetic Jets on Multiscale Features in Wall-Bounded Turbulence |
| title_sort | influence of synthetic jets on multiscale features in wall bounded turbulence |
| topic | active control multiscale synthetic jet turbulent boundary layer |
| url | https://www.mdpi.com/2076-0825/11/7/199 |
| work_keys_str_mv | AT biaohuili influenceofsyntheticjetsonmultiscalefeaturesinwallboundedturbulence AT jinhaozhang influenceofsyntheticjetsonmultiscalefeaturesinwallboundedturbulence AT nanjiang influenceofsyntheticjetsonmultiscalefeaturesinwallboundedturbulence |