Varicose instabilities in turbulent boundary layers
An investigation of a model of turbulence generation in the wall region of a turbulent boundary layer is made through direct numerical simulations. The model is based on the varicose instability of a streak. First, a laminar boundary layer disturbed by a continuous blowing through a slot is simulate...
| Main Authors: | , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2014
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| Online Access: | https://hdl.handle.net/10356/101661 http://hdl.handle.net/10220/18718 |
| _version_ | 1826124250605420544 |
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| author | Skote, M. Haritonidis, J. H. Henningson, D. S. |
| author2 | School of Mechanical and Aerospace Engineering |
| author_facet | School of Mechanical and Aerospace Engineering Skote, M. Haritonidis, J. H. Henningson, D. S. |
| author_sort | Skote, M. |
| collection | NTU |
| description | An investigation of a model of turbulence generation in the wall region of a turbulent boundary layer is made through direct numerical simulations. The model is based on the varicose instability of a streak. First, a laminar boundary layer disturbed by a continuous blowing through a slot is simulated in order to reproduce and further investigate the results reported from the experiments of Acarlar and Smith [J. Fluid Mech. 175, 43 (1987)]. An isolated streak with an inflectional profile is generated that becomes unstable, resulting in a train of horseshoe vortices. The frequency of the vortex generation is equal to the experimental results. Comparison of the instability characteristics to those predicted through an Orr–Sommerfeld analysis are in good agreement. Second, a direct numerical simulation of a turbulent boundary layer is performed to point out the similarities between the horseshoe vortices in a turbulent and a laminar boundary layer. The characteristics of streaks and the vortical structures surrounding them in a turbulent boundary layer compare well with the model streak. The results of the present study show that one mechanism for the generation of horseshoe vortices in turbulent boundary layers is related to a normal inflectional instability of the streaks. |
| first_indexed | 2024-10-01T06:17:35Z |
| format | Journal Article |
| id | ntu-10356/101661 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T06:17:35Z |
| publishDate | 2014 |
| record_format | dspace |
| spelling | ntu-10356/1016612023-03-04T17:19:51Z Varicose instabilities in turbulent boundary layers Skote, M. Haritonidis, J. H. Henningson, D. S. School of Mechanical and Aerospace Engineering DRNTU::Engineering::Mechanical engineering::Fluid mechanics An investigation of a model of turbulence generation in the wall region of a turbulent boundary layer is made through direct numerical simulations. The model is based on the varicose instability of a streak. First, a laminar boundary layer disturbed by a continuous blowing through a slot is simulated in order to reproduce and further investigate the results reported from the experiments of Acarlar and Smith [J. Fluid Mech. 175, 43 (1987)]. An isolated streak with an inflectional profile is generated that becomes unstable, resulting in a train of horseshoe vortices. The frequency of the vortex generation is equal to the experimental results. Comparison of the instability characteristics to those predicted through an Orr–Sommerfeld analysis are in good agreement. Second, a direct numerical simulation of a turbulent boundary layer is performed to point out the similarities between the horseshoe vortices in a turbulent and a laminar boundary layer. The characteristics of streaks and the vortical structures surrounding them in a turbulent boundary layer compare well with the model streak. The results of the present study show that one mechanism for the generation of horseshoe vortices in turbulent boundary layers is related to a normal inflectional instability of the streaks. Published version 2014-01-28T03:16:29Z 2019-12-06T20:42:27Z 2014-01-28T03:16:29Z 2019-12-06T20:42:27Z 2002 2002 Journal Article Skote, M., Haritonidis, J. H., & Henningson, D. S. (2002). Varicose instabilities in turbulent boundary layers. Physics of fluids, 14(7), 2309-2323. https://hdl.handle.net/10356/101661 http://hdl.handle.net/10220/18718 10.1063/1.1482377 135422 en Physics of fluids © 2002 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/10.1063/1.1482377]. 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. application/pdf |
| spellingShingle | DRNTU::Engineering::Mechanical engineering::Fluid mechanics Skote, M. Haritonidis, J. H. Henningson, D. S. Varicose instabilities in turbulent boundary layers |
| title | Varicose instabilities in turbulent boundary layers |
| title_full | Varicose instabilities in turbulent boundary layers |
| title_fullStr | Varicose instabilities in turbulent boundary layers |
| title_full_unstemmed | Varicose instabilities in turbulent boundary layers |
| title_short | Varicose instabilities in turbulent boundary layers |
| title_sort | varicose instabilities in turbulent boundary layers |
| topic | DRNTU::Engineering::Mechanical engineering::Fluid mechanics |
| url | https://hdl.handle.net/10356/101661 http://hdl.handle.net/10220/18718 |
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