Dissipative flow of liquid 4He in the limit of absolute zero

The problem of dissipative superflow in the absence of normal fluid friction is considered within the hydrodynamic approximation. It is found that microscopic surface roughness gives rise to new mechanisms of dissipative vortex motion and vortex regeneration, accounting not only for the critical velocities at which self-sustaining dissipation becomes possible, but also for the occurrence of discrete dissipative events in oscillating flow