We examine the dynamics of a spiralling slender liquid jet which emerges from a rotating cylindrical drum. Such jets arise in the manufacture of fertiliser and magnesium pellts in the prilling process. Exploiting the slenderness of the jet we determine the steady trajectory of the jet, and find that at leading-order it is a function of the rotation rate of the drum, the surface tension and density of the liquid, the exit speed and exit radius of the jet, the radius of the cylinder, but not of the viscosity of the liquid. We carry out a linear stability analysis of the steady solution, using both inviscid and viscous perturbations, and considering both temporal and spatial stability. We compare our results to experiments, obtaining favourable agreement.
Linear stability analysis of axisymmetric perturbations in imperfectly conducting liquid jets
