Consider an axisymmetric suitable weak solution of 3D incompressible Navier–Stokes equations with nontrivial swirl, v=vrer+vθeθ+vzez. Let z denote the axis of symmetry and r be the distance to the z -axis. If the solution satisfies a slightly supercritical assumption (that is, for 767627cde66628ddec2dee141ba" title="Click to view the MathML source">α∈[0,0.028] when r is small), then we prove that v is regular. This extends the results in [6], [16] and [18] where regularities under critical assumptions, such as , were proven.
As a useful tool in the proof of our main result, an upper-bound estimate to the fundamental solution of the parabolic equation with a critical drift term will be given in the last part of this paper.