1999 Volume 65 Issue 632 Pages 1395-1402
In order to reveal unknown characteristics of complex turbulent passive scalar fields, large eddy simulations in forced convection regimes were performed under several strain conditions, including a flow impingement and a flow separation. By using the simulation results, relations between the dynamic and scalar fields were carefully examined. It was then confirmed that the scalar was transported by a large vortex structure near the examined regions wherever the mean shear vanished, though in the high shear regions, the scalar transport was governed by a coherent structure due to the high shear strain. In addition, a priori explorations were attempted by processing the data, focusing on the derivation of a possible direction for modeling the passive scalar transport in complex strain fields algebraically. The a priori tests suggested that an expanded form of the GGDH model introducing quadratic products of the Reynolds stresses was promising for general flow cases.