Unstable waves on a curved non-Newtonian liquid jet

A spiralling slender non-Newtonian liquid jet emerging from a rapidly rotating orifice is examined. The effect of the non-Newtonian rheology on the trajectory of the jet and its linear instability are determined using a mixture of computational and asymptotic methods. The sizes of the droplets produced by this instability are determined by considering the most unstable wave mode. This enables a quantitative comparison between theoretical and experimental results to be made, by comparing droplet sizes predicted from the theory with experimental measurements. At lower Weber numbers some good points of agreement have been obtained. At higher Weber numbers jet break-up becomes increasingly complex and the possibility of break-up being due to absolute, rather than convective, instability is discussed.