The life of vortex knots and the flow of helicity

What happens if you take a vortex loop - akin to a smoke ring in air - and tie it into a knot or a link? The knottiness (Helicity) of a fluid is a conserved quantity in many idealized situations (such as Euler fluids) offering the potential for fundamental insights into fluid flow. In real fluids, progress has been hindered by lack of accessible experimental systems. I will tell of how to make a vortex knot and link in water, in the wave function of a superfluid (on a computer) and of what happens thence, with an emphasis on universal aspects of the dynamics and the flow of helicity.