On the use of shock-capturing schemes for large-eddy simulation

Numerical simulations of freely decaying isotropic fluid turbulence were pe rformed at various Mach numbers (from 0.2 to 1.0) using known shock-capturi ng Euler schemes (Jameson, TVD-MUSCL, ENO) often employed for aeronautical applications. The objective of these calculations was to evaluate the relev ance of the use of such schemes in the large-eddy simulation (LES) context, The potential of the monotone integrated large-eddy simulation (MILES) app roach was investigated by carrying out computations without viscous diffusi on terms. Although some known physical trends were respected, it is found t hat the small scales of the simulated flow suffer from high numerical dampi ng. In a quasi-incompressible case, this numerical dissipation is tentative ly interpreted in terms of turbulent dissipation, yielding the evaluation o f equivalent Taylor micro-scales, The Reynolds numbers based on these are f ound between 30 and 40, depending on the scheme and resolution (up to 128(3 )). The numerical dissipation is also interpreted in terms of subgrid-scale dissipation in a LES context, yielding equivalent Smagorinsky "constants" which do not level off with time and which remain larger than the commonly accepted values of the classical Smagorinsky constant. On the grounds of te sts with either the Smagorinsky or a dynamic model, the addition of explici t subgrid-scale (SGS) models to shock-capturing Euler codes is not recommen ded. (C) 1999 Academic Press.