SLENDER AXISYMMETRICAL FLUID JETS

Fluid fibres and jets are described, in general, by free boundary Navi er Stokes problems. If the ratio of the cross section of the jet is sm all compared to the axial length scale of the jet or fibre, then the f ree boundary problem can be significantly simplified, and a greatly si mplified system of (nonlinear) partial differential equations obtained In this paper, the broad outline of the method will be discussed, wit h reference to the problem of tapering optical fibres of arbitrary cro ss sectional shape and with reference to symmetric fluid jets. In the latter case, further analysis is possible by looking for transformatio ns that reduce the partial differential equations to ordinary differen tial equations.