title: Velocity intermittency in a buoyancy subrange in a two-dimensional soap film convection experiment.
abstract: In a two-dimensional soap film convection experiment, the velocity fields are found to be strongly intermittent in the buoyancy subrange, which was reported to be nonintermittent in a recent numerical simulation. The structure functions Sq(l)(= <delta(upsilon)l(q)>) exhibit self-similar structures and can be described by power laws l(zetaq) for integers 8 > or = q < or = 1. By extending Kolmogorov's refined similarity hypothesis to our system, an analytical form is derived for the scaling exponent zeta(q) = q/2 + (mu/18)(3q - q2). Our measurements yield mu = 0.42, which is significantly greater than 0.2 found in high Reynolds number turbulence in wind tunnels.
authors.affiliation: Department of Physics, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: X L
authors.initials: XL
authors.lastname: Wu