Phase slip and turbulence in superfluid He4: A vortex mill that works

It is shown that the superfluid turbulence arises as a convective, not an absolute, instability. A continuous source of macroscopic quantized vortices is therefore required, not only to initiate the turbulence, but also to keep the vortex tangle alive. It is demonstrated that a streamwise-pinned, remanent vortex at the channel inlet can act as the fluid dynamical analog of a phase-slip center, injecting vortex filaments into the flow at a steady rate. Several such vortex mills in tandem are sufficient to initiate and sustain the turbulent state. © 1990 The American Physical Society.