  The small-scale statistical properties of velocity circulation in classical
homogeneous and isotropic turbulent flows are assessed through a modeling
framework that brings together the multiplicative cascade and the structural
descriptions of turbulence. We find that vortex structures exhibit
short-distance repulsive correlations, which is evidenced when they are
"tomographically" investigated, by means of planar cuts of the flow, as
two-dimensional vortex gases. This phenomenon is suggested from model
improvements which allow us to obtain an accurate multiscale description of the
intermittent fluctuations of circulation. Its crucial new ingredient, the
conjectured hard disk behavior of the effective planar vortices, is then found
to be strongly supported from a study of their spatial distributions in direct
numerical simulations of the Navier-Stokes equations.
