STATISTICAL BALANCE OF VORTICITY AND A NEW SCALE FOR VORTICAL STRUCTURES IN TURBULENCE

The balance of one-point and two-point statistical characteristics of vorticity is considered on the basis of the Navier-Stokes equations. It is shown that within the inertial range of scales (L Re -3/4 << r << L, L external scale, Re Reynolds number) there is a physically distinguished scale l(s) is similar to L Re -3/10. The balance of vortical correlations with scales r greater-than-or-equal-to l(s) is directly affected by the large-scale motion. l(s) is a natural length scale for the ''vortex strings,'' observed experimentally and numerically in three-dimensional turbulent flows. The twist of vortex lines in the internal structure of vortex strings is also briefly discussed.