Reynolds Stress Calculations of Homogeneous Turbulent Shear Flow With Bounded Energy States
INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA
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Reynolds stress calculations of homogeneous turbulent shear flow are conducted with a second-order closure model modified to account for non- equilibrium vortex stretching in the dissipation rate transport equation as recently proposed by Bernard and Speziale J. Fluids Engng. 114, 29 1992. As with the earlier reported K-E model calculations incorporating this vortex stretching effect, a production-equals-dissipation equilibrium is obtained with bounded turbulent kinetic energy and dissipation However, this equilibrium is now not achieved until the dimensionless time St 60 -- an elapsed time that is at least twice as large as any of those considered in previous numerical and physical experiments on homogeneous shear flow. Direct quantitative comparisons between the model predictions and the results of experiments are quite favorable. In particular, is is shown that the inclusion of this nonequilibrium vortex stretching effect has the capability of explaining the significant range of production to dissipation ratios observed in experiments.
- Fluid Mechanics