Algebraic stress modeling in a buoyancy controlled turbulent shear flow

The paper presents an application of the algebraic stress modeling (ASM) technique to the prediction of the flow in a turbulent round buoyant jet. In the ASM approach, algebraic formulas are obtained for the Reynolds stresses and for the components of the turbulent heat flux. In the model used here, transport equations are solved for the turbulence kinetic energy, its dissipation, and the mean square temperature fluctuations. The study shows that buoyancy increases the rate of dissipation of mean square temperature fluctuations above the values indicated by previous recommendations for the modeling of that quantity. As a possible explanation for this result it is suggested that buoyancy introduces anisotropy in the fluctuations at the dissipation scale.