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Long-time behavior of material-surface curvature in isotropic turbulenceThe behavior at large times of the curvature of material elements in turbulence is investigated using Lagrangian velocity-gradient time series obtained from direct numerical simulations of isotropic turbulence. The main objectives are: to study the asymptotic behavior of the pdf curvature as a function of initial curvature and shape; and to establish whether the curvature of an initially plane material element goes to a stationary probability distribution. The evidence available in the literature about the asymptotic curvature-pdf of initially flat surfaces is ambiguous, and the conjecture is that it is quasi-stationary. In this work several material-element ensembles of different initial curvatures and shapes are studied. It is found that, at long times the moments of the logarithm of curvature are independent of the initial pdf of curvature. This, it is argued, supports the view that the curvature attains a stationary distribution at long times. It is also shown that, irrespective of initial shape or curvature, the shape of any material element at long times is cylindrical with a high probability.
Document ID
19940035752
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Girimaji, S. S.
(Analytical Services and Materials, Inc.; NASA, Langley Research Center Hampton, VA, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1992
Publication Information
Publication: In: Studies in turbulence (A94-12376 02-34)
Publisher: Springer-Verlag
Subject Category
Fluid Mechanics And Heat Transfer
Accession Number
94A12407
Funding Number(s)
CONTRACT_GRANT: AF-AFOSR-88-0052
Distribution Limits
Public
Copyright
Other

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