圧縮性一様等方性乱流の直接数値計算とモデルの提案

概要

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In this study, compressibility effects on turbulence were analized by performing Direct Numerical Simulations (DNS) of compressible isotropic turbulence. In compressible turbulence, there are two dilatational terms ; dilatation dissipation (ε_d) and pressure-dilatation correlation (PD), and one solenoidal term ; solenoidal dissipation (ε_s). These terms influence the decay rate of turbulent kinetic energy. Dilatation dissipation is inherent in compressible turbulence and is affected only by the dilatational velocity field. 0n the other hand, solenoidal dissipation is determined by the solenoidal field. Using the Helmholtz decomposition of the velocity field into solenoidal and dilatational components, turbulent kinetic energy was divided into two parts : a solenoidal part (q^2_I) and a dilatational part (q^2_c). The relationship among q^2_I, q^2_c, ε_s and ε_d was introduced by using the energy spectrum, and DNS results were shown to be in good agreement with this relationship. The role of PD and the asymptotic values of the dilatational part of turbulent kinetic energy or pressure fluctuation variance were also analized. Finally, a new model for turbulent kinetic energy and pressure fluctuation in compressible isotropic turbulence was proposed.
一般社団法人日本機械学会の論文
1993-03-25