Vortex stretching and enhanced dissipation for the incompressible 3D Navier–Stokes equations

We consider the 3D incompressible Navier–Stokes equations under the following $$2+\frac{1}{2}$$-dimensional situation: small-scale horizontal vortex blob being stretched by large-scale, anti-parallel pairs of vertical vortex tubes. We prove enhanced dissipation induced by such vortex-stretching.