Pressure-strain energy redistribution in compressible turbulence: return-to-isotropy versus kinetic-potential energy equipartition. (18th July 2016)

• Record Type: Journal Article
• Authors: Lee, Kurnchul; Venugopal, Vishnu; Girimaji, Sharath S
• Is Part Of: Physica scripta. Volume 91:Number 8(2016:Aug.)
• Publication Date: 2016-07-18
• Subjects: turbulence -- direct numerical simulations -- equipartition -- scalar mixing -- scalar dissipation -- inhomogeneous medium; 47.27.Gs -- 47.27.E- -- 47.27.ek; Physics -- Periodicals; 530.05
• DOI: 10.1088/0031-8949/91/8/084006
• Languages: English
• ISSNs: 0031-8949

Abstract

Abstract: Return-to-isotropy and kinetic-potential energy equipartition are two fundamental pressure-moderated energy redistributive processes in anisotropic compressible turbulence. Pressure-strain correlation tensor redistributes energy among various Reynolds stress components and pressure-dilatation is responsible for energy reallocation between dilatational kinetic and potential energies. The competition and interplay between these pressure-based processes are investigated in this study. Direct numerical simulations (DNS) of low turbulent Mach number dilatational turbulence are performed employing the hybrid thermal Lattice Boltzman method (HTLBM). It is found that a tendency towards equipartition precedes proclivity for isotropization. An evolution towards equipartition has a collateral but critical effect on return-to-isotropy. The preferential transfer of energy from strong (rather than weak) Reynolds stress components to potential energy accelerates the isotropization of dilatational fluctuations. Understanding of these pressure-based redistributive processes is critical for developing insight into the character of compressible turbulence.