Anisotropic eddy-viscosity concept for strongly detached unsteady flows

An alternative method, called the Organized Eddy Simulation, was proposed to derive a tensorial eddy-viscosity model sensitized for stress-strain misalignment and nonequilibrium turbulence. The new method was based on findings of several studies that reached the prediction of massively detached unsteady turbulent flows around bodies by a reconsideration of the eddy-diffusion coefficient in two-equation models, derived from differential Renolds stress modeling (DRSM). The new method also used Boussinesq law as a first step, to provide an anisotropic analysis, corressponding more to the flow physics. A physical analysis of the stress-strain angles was also carried out on the basis of a detailed high-Renolds particle image velocimetry (PIV). Anisotropic misalignment criteria were also investigated, producing a definition of the eddy viscocity and leading to a new definition of the Reynolds stress constitutive law.