A Model of Interacting Navier-Stokes Singularities.

We introduce a model of interacting singularities of Navier-Stokes equations, named pinçons. They follow non-equilibrium dynamics, obtained by the condition that the velocity field around these singularities obeys locally Navier-Stokes equations. This model can be seen as a generalization of the vorton model of Novikov that was derived for the Euler equations.

About Universality and Thermodynamics of Turbulence.

This paper investigates the universality of the Eulerian velocity structure functions using velocity fields obtained from the stereoscopic particle image velocimetry (SPIV) technique in experiments and direct numerical simulations (DNS) of the Navier-Stokes equations. It shows that the numerical and experimental velocity structure functions up to order 9 follow a log-universality (Castaing et al. 1993); this leads to a collapse on a universal curve, when units including a logarithmic dependence on the Reynolds number are used.