Influence of velocity spatiotemporal correlations on the anomalous scaling exponents of passive scalars

摘要

In this paper,we consider spatial-temporal correlation functions of the turbulent velocities.With numerical simulations on the Gledzer-Ohkitani-Yamada (GOY) shell model,we show that the correlation function decays exponentially.The advecting velocity field is regarded as a colored noise field,which is spatially and temporally correlative.For comparison,we are also given the scaling exponents of passive scalars obtained by the Gaussian random velocity field,the multi-dimensional normal velocity field and the She-Leveque velocity field,introduced by She,et al.We observe that extended self-similarity scaling exponents H(p)/H(2) of passive scalar obtained by the colored noise field are more anomalous than those obtained by the other three velocity fields.