“…According to K41 universality hypotheses, the structure function should be isotropic and C 0 should have a universal value for all turbulent flows (at least in the limit of high Reynolds number). It is an important parameter in stochastic models of turbulent transport and dispersion (RODEAN, 1991;Sawford, 1991;Weinman and Klimenko, 2000) and is, remarkably, also connected to the structure functions of the fluctuations of a scalar field passively advected by the turbulence (Sawford, 2001). Previously measured values of C 0 range from 2.1 to 7.0, in part because Lagrangian experiments, where the trajectories of individual fluid particles are followed, have historically been very difficult.…”