Cause of jet of vortex ring and its suppression in circular converging nozzle with entrance pipe
The control of circular jets has been studied extensively in the fluid dynamics literature. Most studies introduce an entrance pipe upstream of the nozzle outlet to straighten the flow. In this study, we studied the free jet emitted from a circular nozzle that converges with the entrance pipe. We id...
| Main Authors: | , |
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| Format: | Article |
| Language: | Japanese |
| Published: |
The Japan Society of Mechanical Engineers
2019-07-01
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| Series: | Nihon Kikai Gakkai ronbunshu |
| Subjects: | |
| Online Access: | https://www.jstage.jst.go.jp/article/transjsme/85/876/85_19-00160/_pdf/-char/en |
| _version_ | 1797988977032036352 |
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| author | Masato AKIMOTO Motoaki KIMURA |
| author_facet | Masato AKIMOTO Motoaki KIMURA |
| author_sort | Masato AKIMOTO |
| collection | DOAJ |
| description | The control of circular jets has been studied extensively in the fluid dynamics literature. Most studies introduce an entrance pipe upstream of the nozzle outlet to straighten the flow. In this study, we studied the free jet emitted from a circular nozzle that converges with the entrance pipe. We identified the cause of the naturally occurring vortex ring at the beginning of the jet, and we designed a mechanical intervention that suppresses the vortex. This experiment was performed at Reynolds number Re = 1400–5600. In the experiment, the visualized jet cross section and the flow velocity measured by the hot-wire anemometer were processed with a fast Fourier transform to determine the frequency at which the vortex ring arises. The frequency of the naturally occurring vortex ring depends on acoustic resonance inside the nozzle and is affected by the length of the entrance pipe. Also, the generation frequency of the vortex ring did not increase linearly with Re, but instead increased in discrete steps. A nozzle modification was also tested, with an acoustic material installed inside the nozzle to suppress pressure fluctuations caused by resonance inside the nozzle. This test was performed at Re = 2000, 5000, and 8000. The acoustic material suppressed the naturally occurring vortex ring, which reduced jet diffusion. |
| first_indexed | 2024-04-11T08:12:57Z |
| format | Article |
| id | doaj.art-c15b6d9d8ca24913aa384144eca11439 |
| institution | Directory Open Access Journal |
| issn | 2187-9761 |
| language | Japanese |
| last_indexed | 2024-04-11T08:12:57Z |
| publishDate | 2019-07-01 |
| publisher | The Japan Society of Mechanical Engineers |
| record_format | Article |
| series | Nihon Kikai Gakkai ronbunshu |
| spelling | doaj.art-c15b6d9d8ca24913aa384144eca114392022-12-22T04:35:16ZjpnThe Japan Society of Mechanical EngineersNihon Kikai Gakkai ronbunshu2187-97612019-07-018587619-0016019-0016010.1299/transjsme.19-00160transjsmeCause of jet of vortex ring and its suppression in circular converging nozzle with entrance pipeMasato AKIMOTO0Motoaki KIMURA1College of Science and Technology, Nihon UniversityCollege of Science and Technology, Nihon UniversityThe control of circular jets has been studied extensively in the fluid dynamics literature. Most studies introduce an entrance pipe upstream of the nozzle outlet to straighten the flow. In this study, we studied the free jet emitted from a circular nozzle that converges with the entrance pipe. We identified the cause of the naturally occurring vortex ring at the beginning of the jet, and we designed a mechanical intervention that suppresses the vortex. This experiment was performed at Reynolds number Re = 1400–5600. In the experiment, the visualized jet cross section and the flow velocity measured by the hot-wire anemometer were processed with a fast Fourier transform to determine the frequency at which the vortex ring arises. The frequency of the naturally occurring vortex ring depends on acoustic resonance inside the nozzle and is affected by the length of the entrance pipe. Also, the generation frequency of the vortex ring did not increase linearly with Re, but instead increased in discrete steps. A nozzle modification was also tested, with an acoustic material installed inside the nozzle to suppress pressure fluctuations caused by resonance inside the nozzle. This test was performed at Re = 2000, 5000, and 8000. The acoustic material suppressed the naturally occurring vortex ring, which reduced jet diffusion.https://www.jstage.jst.go.jp/article/transjsme/85/876/85_19-00160/_pdf/-char/enjetvortexjet diffusionvelocity profileacoustic resonance |
| spellingShingle | Masato AKIMOTO Motoaki KIMURA Cause of jet of vortex ring and its suppression in circular converging nozzle with entrance pipe Nihon Kikai Gakkai ronbunshu jet vortex jet diffusion velocity profile acoustic resonance |
| title | Cause of jet of vortex ring and its suppression in circular converging nozzle with entrance pipe |
| title_full | Cause of jet of vortex ring and its suppression in circular converging nozzle with entrance pipe |
| title_fullStr | Cause of jet of vortex ring and its suppression in circular converging nozzle with entrance pipe |
| title_full_unstemmed | Cause of jet of vortex ring and its suppression in circular converging nozzle with entrance pipe |
| title_short | Cause of jet of vortex ring and its suppression in circular converging nozzle with entrance pipe |
| title_sort | cause of jet of vortex ring and its suppression in circular converging nozzle with entrance pipe |
| topic | jet vortex jet diffusion velocity profile acoustic resonance |
| url | https://www.jstage.jst.go.jp/article/transjsme/85/876/85_19-00160/_pdf/-char/en |
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