The Richardson's Law in Large-Eddy Simulations of Boundary Layer flows

Relative dispersion in a neutrally stratified planetary boundary layer (PBL) is investigated by means of large-eddy simulations (LES). Despite the small extension of the inertial range of scales in the simulated PBL, our Lagrangian statistics turn out to be com- patible with the Richardson t3 law for the average of square particle separation, where t is time. This emerges from the application of non-standard methods of analysis through which a precise measure of the Richardson constant was also possible. Its value is estimated as C2=0:5, in close agreement with recent experiments and three-dimensional direct numerical simulations.