title: Passive scalar intermittency in low temperature helium flows.
abstract: We report new measurements of mixing of passive temperature field in a turbulent flow. The use of low temperature helium gas allows us to span a range of microscale Reynolds number, R(lambda), from 100 to 650. The exponents xi(n) of the temperature structure functions </straight theta(x+r)-straight theta(x)/(n)> approximately r(xi(n)) are shown to saturate to xi(infinity) approximately 1.45+/-0.1 for the highest orders, n approximately 10. This saturation is a signature of statistics dominated by frontlike structures, the cliffs. Statistics of the cliffs' characteristics are performed, particularly their widths are shown to scale as the Kolmogorov length scale.
authors.affiliation: Laboratoire de Physique Statistique, ENS, 24 rue Lhomond, 75231 Paris Cedex 05, France.
authors.forename: F
authors.initials: F
authors.lastname: Moisy
authors.forename: H
authors.initials: H
authors.lastname: Willaime
authors.forename: J S
authors.initials: JS
authors.lastname: Andersen
authors.forename: P
authors.initials: P
authors.lastname: Tabeling