Modeling the Pressure-Dilatation Correlation
INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA
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It is generally accepted that the pressure dilatation, which is an additional compressibility term in the turbulence transport equations, may be important for high-speed flows. Recent direct simulations of homogeneous shear turbulence have given concrete evidence that the pressure-dilatation is important insofar that it contributes to the reduced growth of turbulent kinetic energy due to compressibility effects. The present work addresses the problem of modeling the pressure-dilatation. We first isolate a component of the pressure- dilatation which exhibits temporal oscillations and, using direct numerical simulations of homogeneous shear turbulence and isotropic turbulence, show that it has a negligible contribution to the evolution of turbulent kinetic energy. Then, an analysis for the case of homogeneous turbulence is performed to obtain a model for the non-oscillatory pressure dilatation. This model algebraically relates the pressure-dilatation to quantities traditionally obtained in incompressible turbulence closures. The model is validated by direct comparison with the pressure-dilatation data obtained from the simulations.
- Fluid Mechanics