A mass invariant in a compressible turbulent medium
The study introduces a mass invariant, Minv, to predict measurable statistical properties of density fluctuations in supersonic compressible turbulence. Numerical tests confirm Minv remains constant during the decaying phase, providing a parameter-free way to relate non-Gaussian evolution to the logdensity variance. The work models correlation length evolution and shows Minv's Mach number independence in the supersonic regime.