An incompressible liquid flows steadily from a circular orifice and falls freely under the influence of gravity in the form of an axially-symmetrio free jet. The effects of surface tension and viscosity upon the shape of the jet, and upon the flow within the jet, are investigated. Interest is confined to the region of the jet well away from the orifice, as this allows the use of a co-ordinate expansion technique. It is found that in this region the effect of an increase in the coefficient of surface tension is an increase in the radius of the jet, regardless of any imposed conditions at the orifice. Similarly it is found that, at least for sufficiently small Reynolds numbers, an increase in the coefficient of viscosity also leads to an increase in the jet radius, provided that the volume flux of liquid in the jet remains the same. © 1969 Oxford University Press.
