The mixing of scales in shearless turbulent flow

The objective of this experience is to study an example of complex turbulent flow produced by two coflows with the same velocity which presents a mixing of scales. This type of flow produces spectral perturbations with interactions between structures with different sizes. The experimental system produces the mixing of a primary pow into two secondary flows, these flows are supplied by two types of honeycombs producing turbulence and that can be differently combined. The motivation of this study is the development of turbulence models applicable in non-equilibrium situations. The experimental contribution presented here is aimed at describing the effects of the honeycombs on spectral distributions. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.