Transition induced by linear and nonlinear perturbation growth in flow past a compressor blade
Flow past a NACA 65 blade at chord-based Reynolds number 138;500 is studied using stability analysis, generalised (spatially weighted) transient growth analysis and direct numerical simulations (DNS). The mechanisms of transition on various sections of the blade observed in previous work (Zaki et al...
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| Format: | Article |
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Cambridge University Press
2017
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| Online Access: | https://eprints.nottingham.ac.uk/41885/ |
| _version_ | 1848796375038296064 |
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| author | Mao, Xuerui Zaki, T.A. Sherwin, S.J. Blackburn, H.M. |
| author_facet | Mao, Xuerui Zaki, T.A. Sherwin, S.J. Blackburn, H.M. |
| author_sort | Mao, Xuerui |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | Flow past a NACA 65 blade at chord-based Reynolds number 138;500 is studied using stability analysis, generalised (spatially weighted) transient growth analysis and direct numerical simulations (DNS). The mechanisms of transition on various sections of the blade observed in previous work (Zaki et al. 2010) are examined, with a focus on the pressure side around the leading edge. In this region, the linearly most energetic perturbation has spanwise wavenumber 40π (five boundary layer thicknesses) and is tilted against the mean shear to take advantage of the Orr mechanism. In a DNS, the nonlinear development of this optimal perturbation induces ˄ structures, which are further stretched to hairpin vortices before breaking down to turbulence. At higher spanwise wavenumber, e.g. 120π, a free-stream optimal perturbation is obtained upstream of the leading edge, in the form of streamwise vortices. During its nonlinear evolution, this optimal perturbation tilts the mean shear and generates spanwise periodic high and low-speed streaks. Then through a nonlinear lift-up mechanism, the low-speed streaks are lifted above the high speed ones. This layout of streaks generates a mean shear with two in inflectional points, and activates secondary instabilities, namely inner and outer instabilities previously reported in the literature. |
| first_indexed | 2025-11-14T19:46:59Z |
| format | Article |
| id | nottingham-41885 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:46:59Z |
| publishDate | 2017 |
| publisher | Cambridge University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-418852020-05-04T18:49:26Z https://eprints.nottingham.ac.uk/41885/ Transition induced by linear and nonlinear perturbation growth in flow past a compressor blade Mao, Xuerui Zaki, T.A. Sherwin, S.J. Blackburn, H.M. Flow past a NACA 65 blade at chord-based Reynolds number 138;500 is studied using stability analysis, generalised (spatially weighted) transient growth analysis and direct numerical simulations (DNS). The mechanisms of transition on various sections of the blade observed in previous work (Zaki et al. 2010) are examined, with a focus on the pressure side around the leading edge. In this region, the linearly most energetic perturbation has spanwise wavenumber 40π (five boundary layer thicknesses) and is tilted against the mean shear to take advantage of the Orr mechanism. In a DNS, the nonlinear development of this optimal perturbation induces ˄ structures, which are further stretched to hairpin vortices before breaking down to turbulence. At higher spanwise wavenumber, e.g. 120π, a free-stream optimal perturbation is obtained upstream of the leading edge, in the form of streamwise vortices. During its nonlinear evolution, this optimal perturbation tilts the mean shear and generates spanwise periodic high and low-speed streaks. Then through a nonlinear lift-up mechanism, the low-speed streaks are lifted above the high speed ones. This layout of streaks generates a mean shear with two in inflectional points, and activates secondary instabilities, namely inner and outer instabilities previously reported in the literature. Cambridge University Press 2017-06-10 Article PeerReviewed Mao, Xuerui, Zaki, T.A., Sherwin, S.J. and Blackburn, H.M. (2017) Transition induced by linear and nonlinear perturbation growth in flow past a compressor blade. Journal of Fluid Mechanics, 820 . pp. 604-632. ISSN 1469-7645 Boundary layer receptivity; Transition to turbulence https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/transition-induced-by-linear-and-nonlinear-perturbation-growth-in-flow-past-a-compressor-blade/F36FB0E44B4F4323A3E14047591B5E35 doi:10.1017/jfm.2017.240 doi:10.1017/jfm.2017.240 |
| spellingShingle | Boundary layer receptivity; Transition to turbulence Mao, Xuerui Zaki, T.A. Sherwin, S.J. Blackburn, H.M. Transition induced by linear and nonlinear perturbation growth in flow past a compressor blade |
| title | Transition induced by linear and nonlinear perturbation growth in flow past a compressor blade |
| title_full | Transition induced by linear and nonlinear perturbation growth in flow past a compressor blade |
| title_fullStr | Transition induced by linear and nonlinear perturbation growth in flow past a compressor blade |
| title_full_unstemmed | Transition induced by linear and nonlinear perturbation growth in flow past a compressor blade |
| title_short | Transition induced by linear and nonlinear perturbation growth in flow past a compressor blade |
| title_sort | transition induced by linear and nonlinear perturbation growth in flow past a compressor blade |
| topic | Boundary layer receptivity; Transition to turbulence |
| url | https://eprints.nottingham.ac.uk/41885/ https://eprints.nottingham.ac.uk/41885/ https://eprints.nottingham.ac.uk/41885/ |