Transition to dilatation-dominated compressible turbulence

TL;DR

This study investigates the transition to shock-dominated turbulence in compressible flows, revealing a shift from incompressible to shock-dominated regimes at higher Mach numbers through high-resolution simulations.

Contribution

It provides a detailed analysis of the transition to dilatation-dominated turbulence using moments of energy dissipation up to order 4 across a range of Mach numbers.

Findings

Crossover from incompressible to shock-dominated turbulence at M_t ≈ 1

Moment scaling becomes M_t-independent in the shock regime

Shocks statistically dominate energy dissipation at high Mach numbers

Abstract

The kinetic energy dissipation rate is of central importance for the small-scale statistics in turbulent flows. Here, we determine the transition to the dilatation-dominated regime of 3d fully compressible, homogeneous, isotropic turbulence by moments of energy dissipation and its components up to order 4 for turbulent Mach numbers $0.1\le M_t\le 10$. Our high-resolution numerical simulations show a crossover from incompressible to $M_t$-independent, Burgers turbulence-like moment scaling with respect to Reynolds number $Re$. This confirms the statistical dominance of shocks for $M_t\gtrsim 1$.