Second order modeling of boundaryfree turbulent shear flows
Abstract
A set of realizable second order models for boundaryfree turbulent flows is presented. The constraints on second order models based on the realizability principle are reexamined. The rapid terms in the pressure correlations for both the Reynolds stress and the passive scalar flux equations are constructed to exactly satisfy the joint realizability. All other model terms (returntoisotropy, third moments, and terms in the dissipation equations) already satisfy realizability. To correct the spreading rate of the axisymmetric jet, an extra term is added to the dissipation equation which accounts for the effect of mean vortex stretching on dissipation. The test flows used in this study are the mixing shear layer, plane jet, axisymmetric jet, and plane wake. The numerical solutions show that the unified model equations predict all these flows reasonably. It is expected that these models would be suitable for more complex and critical flows.
 Publication:

Space Manufacturing 8  Energy and Materials from Space
 Pub Date:
 June 1991
 Bibcode:
 1991aiaa.confY....S
 Keywords:

 Jet Flow;
 Mixing Layers (Fluids);
 Reynolds Stress;
 Shear Flow;
 Shear Layers;
 Turbulent Flow;
 Turbulent Wakes;
 Vortices;
 Axisymmetric Flow;
 Mathematical Models;
 NavierStokes Equation;
 Scalars;
 Fluid Mechanics and Heat Transfer