Modelling of the decay of kinetic energy and temperature in isotropic turbulence
Abstract
The stochastic model EDQNM (eddydamped quasinormal Markovian) is used to study the dynamics of a passive scalar in threedimensional isotropic turbulence. Starting with energy and temperature spectra concentrated at a low wave number, without external forcing, it is shown numerically that the temperature gradient variance diverges with the enstrophy at a finite time when the viscosity goes to zero and the Prandtl number remains finite. Before this critical time t(c), the kinetic energy and the temperature variance are conserved; after t(c) they are dissipated at a finite rate. For larger times, the kinetic energy and the temperature variance time decay exponents are determined with respect to the infrared behavior of the initial spectra and the relative position of the temperature and velocity integral scales.
 Publication:

9th Australasian Fluid Mechanics Conference
 Pub Date:
 1987
 Bibcode:
 1987aafm.conf..117L
 Keywords:

 Energy Spectra;
 Isotropic Turbulence;
 Kinetic Energy;
 Stochastic Processes;
 Temperature Gradients;
 Three Dimensional Flow;
 Computational Fluid Dynamics;
 Energy Dissipation;
 Energy Methods;
 Entropy;
 Prandtl Number;
 Richardson Number;
 Fluid Mechanics and Heat Transfer