Renormalization group, operator product expansion and anomalous scaling in models of passive turbulent advection

Abstract

The field theoretic renormalization group is applied to Kraichnan's model of a passive scalar quantity advected by the Gaussian velocity field with the pair correlation function $\proptoδ(t-t')/k^{d+ε}$. Inertial-range anomalous scaling for the structure functions and various pair correlators is established as a consequence of the existence in the corresponding operator product expansions of ``dangerous'' composite operators (powers of the local dissipation rate), whose {\it negative} critical dimensions determine anomalous exponents. The latter are calculated to order $ε^3$ of the $ε$ expansion (three-loop approximation).