FORWARD AND BACKWARD SPECTRAL TRANSFER IN THE MODELING OF SCALAR MIXING IN HOMOGENEOUS TURBULENCE

摘要

High-resolution direct numerical simulation (DNS) data are employed to extract scalar transfer spectra and related quantities for the validation of a finite-wavenumber-band spectral model for turbulent scalar mixing. Scalar-variance and covariance spectra are investigated for Schmidt numbers ranging from 1/8 to 1 and for Taylor-scale Reynolds number ranging from 90 to 230. The DNS data generally confirm the model assumptions, but also provide new insights into the Schmidt and Reynolds number dependence of model parameters.