ISSN:
1089-7666
Source:
AIP Digital Archive
Topics:
Physics
Notes:
We report measurements of the probability distribution function of the velocity derivatives, and the corresponding hyperflatness factors, up to order 6, as a function of the microscale Reynolds number Rλ. The measurements are performed in a flow produced between counter-rotating disks, using low-temperature helium gas as the working fluid, in a range of microscale Reynolds numbers lying between 150 and 2300. Consistently with previous studies, a transitional behavior is found around Rλ(approximate)700. We determine a simple scaling law, in terms of Rλ, which allows the collapse of the tails of the pdf of the velocity derivatives onto a single curve, below the transition. We find well-defined relative power laws for the hyperflatness factors Hp and Hp*, throughout the entire range of variation of Rλ: H4=F=(0.99±0.05)H60.376±0.015 and H5*=(0.95±0.05)H60.67±0.022. These results are compared to those of previous investigators and to various theoretical approaches both statistical (multifractal model) and structural (i.e., based on a model of fine scales). © 1997 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.869484
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