Development and Validation of RNG Methodology for Compressible Turbulence
Final rept. 1 Apr 1989-31 Mar 1993
PRINCETON UNIV NJ DEPT OF AEROSPACE AND MECHANICAL SCIENCES
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All three different categories of tasks described in our AFOSR proposal Grant 90-0261 were completed successfully a Development of Renormalization Group theory RNG for compressible turbulence b Design and Measurements of a compressible boundary layer experiment, and c Development of spectral element algorithms for compressible flows. A brief summary follows On the theoretical side first, the new results obtained for compressible turbulence are 1 At the large scales the effective sound velocity in compressible turbulence is scale-dependent and obeys a universal equation of state. 2 The effective, scale-dependent Mach number based on the rms value of velocity approaches a fixed point corresponding to effectively subsonic flow. 3 The potential component of the velocity field sound waves does not alter the scaling of the energy spectrum of incompressible rotational component. This decoupling of events in rotational and compressibility effects suggests that most of the RNG modeling for incompressible flows is also valid for compressible flows as long as compressibility is taken into account.
- Fluid Mechanics