Identifying turbulent spots in transitional boundary layers
An artificial turbulent spot is simulated in a zero free-stream turbulence base flow and a base flow with organised streaks. Six identification methods are used in order to isolate the turbulent spot from the surrounding non-turbulent fluid. These are (i) instantaneous wall-normal velocity, v′, (ii)...
| मुख्य लेखकों: | , , , , , |
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| स्वरूप: | Journal article |
| भाषा: | English |
| प्रकाशित: |
2011
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| _version_ | 1826286253784432640 |
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| author | Rehill, B Walsh, E Schlatter, P Brandt, L Zaki, T McEligot, D |
| author_facet | Rehill, B Walsh, E Schlatter, P Brandt, L Zaki, T McEligot, D |
| author_sort | Rehill, B |
| collection | OXFORD |
| description | An artificial turbulent spot is simulated in a zero free-stream turbulence base flow and a base flow with organised streaks. Six identification methods are used in order to isolate the turbulent spot from the surrounding non-turbulent fluid. These are (i) instantaneous wall-normal velocity, v′, (ii) instantaneous spanwise velocity, w′, (iii) instantaneous turbulent dissipation, (iv) λ2 - criterion, (v) Q - criterion and (vi) gradient of the Finite Time Lyapunov Exponent. All methods are effective in isolating the turbulent spot from the streaks. The robustness of each technique is determined from the sensitivity of the maximum spot dimensions to changes in threshold level. The Q-criterion shows the least sensitivity for the zero free-stream turbulence case and the instantaneous turbulent dissipation technique is least sensitive in the organised streaks case. For both cases the v′ technique was the most sensitive to changes in threshold level. Copyright © 2011 by ASME. |
| first_indexed | 2024-03-07T01:41:01Z |
| format | Journal article |
| id | oxford-uuid:96d92265-2ac5-479d-89d2-0bd0b3b57de1 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T01:41:01Z |
| publishDate | 2011 |
| record_format | dspace |
| spelling | oxford-uuid:96d92265-2ac5-479d-89d2-0bd0b3b57de12022-03-26T23:55:46ZIdentifying turbulent spots in transitional boundary layersJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:96d92265-2ac5-479d-89d2-0bd0b3b57de1EnglishSymplectic Elements at Oxford2011Rehill, BWalsh, ESchlatter, PBrandt, LZaki, TMcEligot, DAn artificial turbulent spot is simulated in a zero free-stream turbulence base flow and a base flow with organised streaks. Six identification methods are used in order to isolate the turbulent spot from the surrounding non-turbulent fluid. These are (i) instantaneous wall-normal velocity, v′, (ii) instantaneous spanwise velocity, w′, (iii) instantaneous turbulent dissipation, (iv) λ2 - criterion, (v) Q - criterion and (vi) gradient of the Finite Time Lyapunov Exponent. All methods are effective in isolating the turbulent spot from the streaks. The robustness of each technique is determined from the sensitivity of the maximum spot dimensions to changes in threshold level. The Q-criterion shows the least sensitivity for the zero free-stream turbulence case and the instantaneous turbulent dissipation technique is least sensitive in the organised streaks case. For both cases the v′ technique was the most sensitive to changes in threshold level. Copyright © 2011 by ASME. |
| spellingShingle | Rehill, B Walsh, E Schlatter, P Brandt, L Zaki, T McEligot, D Identifying turbulent spots in transitional boundary layers |
| title | Identifying turbulent spots in transitional boundary layers |
| title_full | Identifying turbulent spots in transitional boundary layers |
| title_fullStr | Identifying turbulent spots in transitional boundary layers |
| title_full_unstemmed | Identifying turbulent spots in transitional boundary layers |
| title_short | Identifying turbulent spots in transitional boundary layers |
| title_sort | identifying turbulent spots in transitional boundary layers |
| work_keys_str_mv | AT rehillb identifyingturbulentspotsintransitionalboundarylayers AT walshe identifyingturbulentspotsintransitionalboundarylayers AT schlatterp identifyingturbulentspotsintransitionalboundarylayers AT brandtl identifyingturbulentspotsintransitionalboundarylayers AT zakit identifyingturbulentspotsintransitionalboundarylayers AT mceligotd identifyingturbulentspotsintransitionalboundarylayers |