Estimation of the Kolmogorov constant C0 by direct numerical simulation of a continuous scalar

Abstract

Kolmogorov constant C0, which determines the effective turbulent diffusion in velocity space, was estimated by using direct numerical simulation (DNS). The results were consistent with the conventional estimations. The initial transient for passive scalar mixing was examined by using probability density function (pdf) and conditional moment analysis. However, C0 obtained by this method was very sensitive to other parameters. The initial values of C0 were found to be very close to 2/3. The coefficient C0, which determines the effective turbulent diffusion in velocity space, is fundamental in Lagrangian modeling. Others, for example, Yeung and Pope [J. Fluid Mech. 207, 531 (1989)] have investigated this coefficient numerically with direct numerical simulation (DNS) by analyzing the dispersion of discrete particles. In our paper we estimate the coefficient C0 by using DNS to study the initial evolution of continuous passive scalar fields. Using an equivalent probability density function (pdf) and conditional moment analyses we examine the initial transient behavior for passive scalar mixing, with both linear and Gaussian-type initial distributions in the velocity space. Our estimates of C0 are found to be consistent with the data found in the literature. © 2000 American Institute of Physics.