Effects of Transverse Disturbances on Disintegration of a Planar Liquid Jet

Disintegrations of a planar liquid jet for three-dimensional disturbances are numerically examined on reduced nonlinear equations derived under the long wave approximation when the surrounding gas density is ignored. In particular, effects of the transverse disturbances are examined on the breakup caused by the longitudinal disturbances propagating along the steady main flow whose velocity is constant or accelerated downward due to the gravitational force. When the sinuous or bulge mode disturbance is given at the nozzle exit in the semi-infinite jet, the following results are obtained for sufficiently long wave transverse disturbances: (i) without the gravity, the breakup time and distance for the longitudinal sinuous mode disturbances are slightly decreased depending upon the wavenumber of the transverse disturbance, while those for the bulge mode disturbances are more decreased but independent of the transverse wavenumber, (ii) the resulting breakup is almost two-dimensional for the sinuous mode, but three-dimensional for the bulge mode, (iii) under the gravitational force, the transversal effects on the decrease of the breakup time and distance are large enhanced for both modes and (iv) the resulting breakup becomes always three-dimensional for both modes.