Dynamics of laminar circular jet impingement upon convex cylinders
Flow dynamics associated with a laminar circular jet impinging upon a convex cylinder has been investigated by laser-induced fluorescence and digital particle-image velocimetry techniques. Cylinder-to-jet diameter ratios of 1, 2, and 4 were investigated, while the jet-to-cylinder separation distance...
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sg-ntu-dr.10356-1073122023-03-04T17:20:16Z Dynamics of laminar circular jet impingement upon convex cylinders New, Daniel Tze How Long, J. School of Mechanical and Aerospace Engineering DRNTU::Engineering::Mechanical engineering::Fluid mechanics Flow dynamics associated with a laminar circular jet impinging upon a convex cylinder has been investigated by laser-induced fluorescence and digital particle-image velocimetry techniques. Cylinder-to-jet diameter ratios of 1, 2, and 4 were investigated, while the jet-to-cylinder separation distance was kept at four jet diameters throughout. Flow visualization and λ2 criterion results show that once the jet ring-vortices impinge upon the cylindrical surface, they move away from the impingement point by wrapping themselves partially around the surface. As the cylinder diameter increases, wall boundary layer separation, vortex dipole formation, and separation locations are initiated earlier along the cylindrical surface, producing significantly larger wakes. Along the cylinder straight-edges, ring-vortex cores are significantly smaller after impingement. This is due to accentuated vortex-stretching caused by partial wrapping around the cylindrical surface by the ring-vortices, on top of their movement away from the impingement point. Interestingly, vortex dipoles demonstrate a strong tendency to travel upstream and interact with other upstream vortex dipoles, instead of moving downstream gradually seen for flat-surface jet-impingements. Wall shear stress results are also presented to quantify the effects of cylinder diameter-ratio on surface skin friction distribution. Finally, these preceding observations are corroborated and explained in a three-dimensional flow dynamics model presented here. Published version 2015-04-13T04:18:21Z 2019-12-06T22:28:41Z 2015-04-13T04:18:21Z 2019-12-06T22:28:41Z 2015 2015 Journal Article New, D. T. H., & Long, J. (2015). Dynamics of laminar circular jet impingement upon convex cylinders. Physics of fluids, 27. 1070-6631 https://hdl.handle.net/10356/107312 http://hdl.handle.net/10220/25385 10.1063/1.4913498 en Physics of fluids © 2015 American Institute of Physics. This paper was published in Physics of fluids and is made available as an electronic reprint (preprint) with permission of American Institute of Physics. The paper can be found at the following official DOI: [http://dx.doi.org/10.1063/1.4913498]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law. 11 p. application/pdf |
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DRNTU::Engineering::Mechanical engineering::Fluid mechanics New, Daniel Tze How Long, J. Dynamics of laminar circular jet impingement upon convex cylinders |
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Flow dynamics associated with a laminar circular jet impinging upon a convex cylinder has been investigated by laser-induced fluorescence and digital particle-image velocimetry techniques. Cylinder-to-jet diameter ratios of 1, 2, and 4 were investigated, while the jet-to-cylinder separation distance was kept at four jet diameters throughout. Flow visualization and λ2 criterion results show that once the jet ring-vortices impinge upon the cylindrical surface, they move away from the impingement point by wrapping themselves partially around the surface. As the cylinder diameter increases, wall boundary layer separation, vortex dipole formation, and separation locations are initiated earlier along the cylindrical surface, producing significantly larger wakes. Along the cylinder straight-edges, ring-vortex cores are significantly smaller after impingement. This is due to accentuated vortex-stretching caused by partial wrapping around the cylindrical surface by the ring-vortices, on top of their movement away from the impingement point. Interestingly, vortex dipoles demonstrate a strong tendency to travel upstream and interact with other upstream vortex dipoles, instead of moving downstream gradually seen for flat-surface jet-impingements. Wall shear stress results are also presented to quantify the effects of cylinder diameter-ratio on surface skin friction distribution. Finally, these preceding observations are corroborated and explained in a three-dimensional flow dynamics model presented here. |
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School of Mechanical and Aerospace Engineering |
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School of Mechanical and Aerospace Engineering New, Daniel Tze How Long, J. |
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Article |
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New, Daniel Tze How Long, J. |
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New, Daniel Tze How |
title |
Dynamics of laminar circular jet impingement upon convex cylinders |
title_short |
Dynamics of laminar circular jet impingement upon convex cylinders |
title_full |
Dynamics of laminar circular jet impingement upon convex cylinders |
title_fullStr |
Dynamics of laminar circular jet impingement upon convex cylinders |
title_full_unstemmed |
Dynamics of laminar circular jet impingement upon convex cylinders |
title_sort |
dynamics of laminar circular jet impingement upon convex cylinders |
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2015 |
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https://hdl.handle.net/10356/107312 http://hdl.handle.net/10220/25385 |
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1759856149644967936 |