title: Intermittent particle distribution in synthetic free-surface turbulent flows.
abstract: Tracer particles on the surface of a turbulent flow have a very intermittent distribution. This preferential concentration effect is studied in a two-dimensional synthetic compressible flow, both in the inertial (self-similar) and in the dissipative (smooth) range of scales, as a function of the compressibility C . The second moment of the concentration coarse grained over a scale r , n_{r};{2} , behaves as a power law in both the inertial and the dissipative ranges of scale, with two different exponents. The shapes of the probability distribution functions of the coarse-grained density n_{r} vary as a function of scale r and of compressibility C through the combination C/r;{kappa} (kappa approximately 0.5) , corresponding to the compressibility, coarse grained over a domain of scale r , averaged over Lagrangian trajectories.
authors.affiliation: Institut Non Linéaire de Nice, CNRS, F-06560 Valbonne, France.
authors.forename: Lauris
authors.initials: L
authors.lastname: Ducasse
authors.forename: Alain
authors.initials: A
authors.lastname: Pumir