Local nonequilibrium dissipation scaling in compressible homogeneous isotropic turbulence

We quantify the nondimensional turbulent kinetic energy dissipation rate, Cε, in compressible homogeneous isotropic turbulence using a direct numerical simulation database sustained by solenoidal linear forcing. Integral-scale Reynolds numbers are ReL0=140, 350, and 900, corresponding to Taylor–microscale Reynolds numbers Reλ≃40–150, and the turbulent Mach number spans MT0=0.3–0.9 in each set. The velocity field is decomposed into solenoidal and dilatational components via the Helmholtz decomposition, and dissipation measures are evaluated consistently for each component. Global statistics of the nondimensional dissipation rate generally agree with those reported in previous studies. A subdomain-based analysis provides a local characterization of dissipation scaling in compressible isotropic turbulence. When conditioned on locally evaluated Reλ, conditional averages of Cε collapse across all cases and follow nonequilibrium scaling, Cε∼Reλ−1, and the solenoidal contribution obeys the same scaling, Cεs∼Reλ−1. In contrast, the dilatational contribution is only weakly dependent on local Reλ and instead correlates with local compressibility, increasing monotonically with the dilatational turbulent Mach number. These results demonstrate that nonequilibrium dissipation is fundamentally local and compressibility enters primarily through intermittent dilatational dynamics.