| Popis: |
Measured profiles of third order scalar-velocity correlations, which appear in the governing equations of Reynolds stress and turbulent heat flux, are presented for the turbulent diffusion field in a homogeneous shear flow. Assessment of previous models for 3rd order moments (Launder’s model, Lumley’s model) using the experimental values of lower order moments and time scales reveal that the accuracies of predictions are different from quantity to quantity. In order to predict the 3rd order moments more accurately, a new composite time scale for the simple gradient transport model is proposed. |
