Streamlines concentration and application to the incompressible   Navier-Stokes equations
  For a smooth domain $D$ containing the origin, we consider a vector field $u \in C^1(D\setminus\{0\},\mathbb{R}^3)$ with $\divg u \equiv 0$ and exclude certain types of possible isolated singularities at the origin, based on the geometry of streamlines that go near that possible singular point. 
Eric Foxall, Slim Ibrahim and Tsuyoshi Yoneda
math.AP