Turbulence and Large-Eddy Simulations

Abstract

After having discussed the limits of turbulence direct-numerical simulations, one presents large-eddy simulations methods, where small scales are filtered out and modelled by appropriate eddy coefficients in the evolution of large scales. We concentrate on models developed originally in Fourier space, then adapted to physical space. One presents coherent-vortex dynamics and statistical data obtained thanks to these models for incompressible isotropic turbulence, channel flow and controlled round jet. Then large-eddy simulations are considered in the compressible case, where we study first the free jet at Mach 0.7 and 1.4, then the controlled supersonic jet. Finally LES of compressible flows above riblets in subsonic and supersonic cases are considered.