Behavior of a turbulent flow, strongly out of equilibrium, at supersonic speeds

Abstract

A study is presented of the mechanisms occurring in a turbulent near wake flow at supersonic speed, in which there exist strong pressure and velocity gradients. The role played by the ’’production’’ of turbulent kinetic energy is shown. It is influenced by compressibility and anisotropy. The analysis indicates that compressibility increases production when a sheared flow develops in a positive pressure gradient, and decreases it in the case of an expansion. The experiments give the mean and turbulent characteristics of a near wake flow. The results show that: the levels of vorticity and entropy modes verify the relationship given by the strong Reynolds analogy; the correlation coefficient between modes is not significantly altered by strong gradients and rates of strain; negative production occurs in the expansion zone; as a consequence, there exists a decrease in turbulence measured downstream of this region.