INTERMITTENCY IN PASSIVE SCALAR ADVECTION

A Lagrangian method for the numerical simulation of the Kraichnan pass ive scalar model is introduced. The method is based on Monte Carlo sim ulations of tracer trajectories, supplemented by a point-splitting pro cedure for coinciding points. Clean scaling behavior for scalar struct ure functions is observed. The scheme is exploited to investigate the dependence of scalar anomalies on the scaling exponent xi of the advec ting velocity field. The three-dimensional fourth-order structure func tion is specifically considered.