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A vorticity stretch...
A vorticity stretching diagnostic for turbulent flows
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- Malm, Johan (författare)
- KTH,Linné Flow Center, FLOW
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- Schlatter, Philipp (författare)
- KTH,Linné Flow Center, FLOW
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Sandham, N. D. (författare)
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(creator_code:org_t)
- International Symposium on Turbulence and Shear Flow Phenomena, TSFP, 2011
- 2011
- Engelska.
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Ingår i: 7th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2011. - : International Symposium on Turbulence and Shear Flow Phenomena, TSFP.
- Relaterad länk:
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http://tsfp10.org/
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visa fler...
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https://urn.kb.se/re...
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Abstract
Ämnesord
Stäng
- Vorticity stretching in wall-bounded turbulent and transitional flows has been investigated by means of a new diagnostic, designed to pick up regions with large amounts of vorticity stretching. It was found that the largest occurrence of vorticity stretching in fully turbulent channel flows is present at a wall-normal distance of y+ = 6.5, i.e. in the transition between the viscous sublayer and the buffer region. Instantaneous data showed that the coherent structures associated with these stretching events have the shape of flat ‘pancake structures’ in the vicinity of high-speed streaks, here denoted ‘h-type’ events. The other event found, also studied in an asymptotic suction boundary layer, is the ‘l-type’ event present on top of an unstable low-speed streak. These events are further thought to be associated with the exponential growth of streamwise vorticity in the turbulent near-wall cycle.
Ämnesord
- TEKNIK OCH TEKNOLOGIER -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)
Nyckelord
- Atmospheric thermodynamics
- Boundary layers
- Channel flow
- Turbulence
- Vorticity
- Buffer region
- Coherent structure
- Exponential growth
- Normal distance
- Pancake structure
- Transitional flow
- Turbulent channel flows
- Viscous sublayer
- Shear flow
Publikations- och innehållstyp
- ref (ämneskategori)
- kon (ämneskategori)