The Relative Dispersion of Particle Pairs in Stationary Homogeneous Turbulence

The relative dispersion of particle pairs in stationary homogeneous turbulence is investigated in numerical simulations using one-dimensional and quasi-one-dimensional Lagrangian stochastic models, satisfying the well-mixed condition for Gaussian and non-Gaussian two-point velocity distribution functions. Predictions for the statistics of particle-pair separations are shown to be sensitively dependent upon third and higher moments of the two-point velocity distribution function. The results of numerical simulations suggest that Lagrangian stochastic models based upon Gaussian two-point velocity distribution functions tend to underpredict the intensity of concentration fluctuations at small times.