The liquid helix: Inertial-capillary adhesion of liquid jets around cylinders

From everyday experience, we all know that a solid edge can deflect a liquid flowing over it significantly, up to the point where the liquid completely sticks to the solid. Although important in pouring, printing and extrusion processes, there is no predictive model of this so-called ``teapot effect''. Here by grazing vertical cylinders with inclined capillary liquid jets, we use the teapot effect to attach the jet to the solid and form a helical rivulet: the liquid helix. We quantitatively predict the shape of the helix by modeling how rivulets relax toward their final velocity and the critical velocity for the helix formation follows from a parameter-free inertial-capillary adhesion model.