Experimental Investigation of the Entrainment Mechanism in Circular and Lobed Hemispherical Jets
Better mixing in the near-field region of jets with their surrounding fluid is of high interest for several industrial applications. Passive control that involves jet geometry modifications as compared to the traditional circular design is used in the present work. An analysis of the entrainment mec...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-07-01
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| Series: | Fluids |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2311-5521/10/7/177 |
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| Summary: | Better mixing in the near-field region of jets with their surrounding fluid is of high interest for several industrial applications. Passive control that involves jet geometry modifications as compared to the traditional circular design is used in the present work. An analysis of the entrainment mechanism in the near jet-exit field is proposed for innovative hemispherical nozzles (circular and six-lobed). High-speed Time-Resolved Particle Image Velocimetry (TR-PIV) measurements are used to experimentally characterize the entrainment mechanism in these jets. The distributions of mean entrainment rates, shear layer growth, and momentum flux are investigated along the longitudinal direction within the near-field region of both circular and lobed hemispherical jets. Significant entrainment enhancement is found using the hemispherical geometry as a passive-control method. By comparing both investigated hemispherical nozzle geometries, it has been demonstrated that the lobed nozzle provides higher mixing rates compared to the circular jet. This enhancement in mixing can be attributed to the stronger streamwise vortex structures generated by the lobed nozzle geometry, which promote increased entrainment of the surrounding fluid. |
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| ISSN: | 2311-5521 |