DOI: 10.1615/TSFP2
EXPERIMENTAL AND MODELLING STUDY OF THE ANISOTROPY OF TEMPERATURE DISSIPATION DOWNSTREAM OF A HEATED LINE SOURCE
RÉSUMÉ
Anisotropic injection of a scalar in a turbulent medium is realized by heating a line source in two kinds of flow namely, a turbulent boundary layer and a turbulent plane jet. In the conditions of those experiments, temperature can be considered as a passive scalar advected by the flow. The three instantaneous temperature gradients are measured. The experimental data show that the second-order moments of the temperature gradients are highly anisotropic near the line source. This anisotropy relaxes with downstream distance. A model representing the evolution of the variance of the temperature gradients is also proposed and enables us to interpret the data and to derive the time scale of the return to isotropy at the level of temperature dissipation.