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Localisation of opt...
Localisation of optimal perturbations in variable viscosity channel flow
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Jose, Sharath (författare)
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- Brandt, Luca (författare)
- KTH,Linné Flow Center, FLOW
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Govindarajan, Rama (författare)
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(creator_code:org_t)
- ELSEVIER SCIENCE INC, 2020
- 2020
- Engelska.
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Ingår i: International Journal of Heat and Fluid Flow. - : ELSEVIER SCIENCE INC. - 0142-727X .- 1879-2278. ; 85
- Relaterad länk:
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https://urn.kb.se/re...
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visa fler...
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https://doi.org/10.1...
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visa färre...
Abstract
Ämnesord
Stäng
- We discuss how a variable fluid viscosity affects the nonmodal stability characteristics of the pressure driven flow between two parallel walls maintained at different temperatures. In this work, we specify the fluid viscosity to be a function of the fluid temperature. We employ an Arrhenius model to model the viscosity of water, and Sutherland's law to model the viscosity of air. We impose a stable density stratification, and find that strong density stratification can suppress optimal transient growth regardless of how strong the viscosity variation is. Some studies have been inclined to neglect viscosity stratification, since the changes in levels of optimal growth, when compared to the uniform viscosity case, are often not too significant. In this article, we show significant localisation of optimal perturbation energy in the less viscous region, a feature that is not observed in uniform viscosity flows. This can have a bearing on the route to turbulence in these systems.
Ämnesord
- TEKNIK OCH TEKNOLOGIER -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)
Nyckelord
- Nonmodal stability
- Variable viscosity
- Localised optimal perturbations
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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