Evolution and Near-Wall Effect of the Vortex Structures Induced by In-Line Twin Synthetic Jets in a Crossflow
This paper aims to further the understanding of the mixing process of in-line twin synthetic jets (SJs) and their impact in the near-wall region in a flat-plate laminar boundary layer. A numerical study has been carried out, in which colored fluid particles and the <i>Q</i> criterion are...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-08-01
|
| Series: | Actuators |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-0825/11/8/234 |
| _version_ | 1827601293687914496 |
|---|---|
| author | Hongxin Wang Degang Xu Linwen Li Kaiwen Zhou Xin Wen Hui Tang |
| author_facet | Hongxin Wang Degang Xu Linwen Li Kaiwen Zhou Xin Wen Hui Tang |
| author_sort | Hongxin Wang |
| collection | DOAJ |
| description | This paper aims to further the understanding of the mixing process of in-line twin synthetic jets (SJs) and their impact in the near-wall region in a flat-plate laminar boundary layer. A numerical study has been carried out, in which colored fluid particles and the <i>Q</i> criterion are used to track the SJ-induced vortex structures at the early stage of the evolution. Interacting vortex structures at four selected phase differences are presented and analyzed. It is found that the fluid injected at the early stage of the blowing stroke mainly contributes to the formation of the hairpin legs, the fluid injected near the maximum blowing mainly contributes to the formation of the hairpin head, and the fluid injected at the late stage of the blowing stroke contributes very little to the formation of the hairpin vortex. It is also confirmed that, irrespective of the phase difference, the hairpin vortex issued from the upstream actuator is more capable of maintaining its coherence than its counterpart issued from the downstream actuator. The influence of the interacting vortex structures on the boundary layer is also studied through investigating excess wall shear stress. In all cases, a pair of streaks of high wall shear stress can be observed with similar size. Among them, the streaks have the strongest wall shear stress, with the largest gap at phase difference 0 when partially interacting vortex structures are produced. The findings can provide valuable guiding information for the applications of synthetic jets in heat transfer, mixing control, and flow control in a crossflow. |
| first_indexed | 2024-03-09T04:52:14Z |
| format | Article |
| id | doaj.art-b292a924c9e642fcb55effb7420634a0 |
| institution | Directory Open Access Journal |
| issn | 2076-0825 |
| language | English |
| last_indexed | 2024-03-09T04:52:14Z |
| publishDate | 2022-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Actuators |
| spelling | doaj.art-b292a924c9e642fcb55effb7420634a02023-12-03T13:09:25ZengMDPI AGActuators2076-08252022-08-0111823410.3390/act11080234Evolution and Near-Wall Effect of the Vortex Structures Induced by In-Line Twin Synthetic Jets in a CrossflowHongxin Wang0Degang Xu1Linwen Li2Kaiwen Zhou3Xin Wen4Hui Tang5School of Automation, Central South University, Changsha 410083, ChinaSchool of Automation, Central South University, Changsha 410083, ChinaShanghai Aircraft Design and Research Institute, Shanghai 201210, ChinaKey Lab of Education Ministry for Power Machinery and Engineering, School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, ChinaKey Lab of Education Ministry for Power Machinery and Engineering, School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, ChinaDepartment of Mechanical Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong, ChinaThis paper aims to further the understanding of the mixing process of in-line twin synthetic jets (SJs) and their impact in the near-wall region in a flat-plate laminar boundary layer. A numerical study has been carried out, in which colored fluid particles and the <i>Q</i> criterion are used to track the SJ-induced vortex structures at the early stage of the evolution. Interacting vortex structures at four selected phase differences are presented and analyzed. It is found that the fluid injected at the early stage of the blowing stroke mainly contributes to the formation of the hairpin legs, the fluid injected near the maximum blowing mainly contributes to the formation of the hairpin head, and the fluid injected at the late stage of the blowing stroke contributes very little to the formation of the hairpin vortex. It is also confirmed that, irrespective of the phase difference, the hairpin vortex issued from the upstream actuator is more capable of maintaining its coherence than its counterpart issued from the downstream actuator. The influence of the interacting vortex structures on the boundary layer is also studied through investigating excess wall shear stress. In all cases, a pair of streaks of high wall shear stress can be observed with similar size. Among them, the streaks have the strongest wall shear stress, with the largest gap at phase difference 0 when partially interacting vortex structures are produced. The findings can provide valuable guiding information for the applications of synthetic jets in heat transfer, mixing control, and flow control in a crossflow.https://www.mdpi.com/2076-0825/11/8/234twin synthetic jetslaminar boundary layervortex interactionsimulation |
| spellingShingle | Hongxin Wang Degang Xu Linwen Li Kaiwen Zhou Xin Wen Hui Tang Evolution and Near-Wall Effect of the Vortex Structures Induced by In-Line Twin Synthetic Jets in a Crossflow Actuators twin synthetic jets laminar boundary layer vortex interaction simulation |
| title | Evolution and Near-Wall Effect of the Vortex Structures Induced by In-Line Twin Synthetic Jets in a Crossflow |
| title_full | Evolution and Near-Wall Effect of the Vortex Structures Induced by In-Line Twin Synthetic Jets in a Crossflow |
| title_fullStr | Evolution and Near-Wall Effect of the Vortex Structures Induced by In-Line Twin Synthetic Jets in a Crossflow |
| title_full_unstemmed | Evolution and Near-Wall Effect of the Vortex Structures Induced by In-Line Twin Synthetic Jets in a Crossflow |
| title_short | Evolution and Near-Wall Effect of the Vortex Structures Induced by In-Line Twin Synthetic Jets in a Crossflow |
| title_sort | evolution and near wall effect of the vortex structures induced by in line twin synthetic jets in a crossflow |
| topic | twin synthetic jets laminar boundary layer vortex interaction simulation |
| url | https://www.mdpi.com/2076-0825/11/8/234 |
| work_keys_str_mv | AT hongxinwang evolutionandnearwalleffectofthevortexstructuresinducedbyinlinetwinsyntheticjetsinacrossflow AT degangxu evolutionandnearwalleffectofthevortexstructuresinducedbyinlinetwinsyntheticjetsinacrossflow AT linwenli evolutionandnearwalleffectofthevortexstructuresinducedbyinlinetwinsyntheticjetsinacrossflow AT kaiwenzhou evolutionandnearwalleffectofthevortexstructuresinducedbyinlinetwinsyntheticjetsinacrossflow AT xinwen evolutionandnearwalleffectofthevortexstructuresinducedbyinlinetwinsyntheticjetsinacrossflow AT huitang evolutionandnearwalleffectofthevortexstructuresinducedbyinlinetwinsyntheticjetsinacrossflow |