Instabiity and Encapsulation of a Compound Liquid Jet

抄録

We analytically examine breakup phenomena of a compound liquid jet which consists of a gas or liquid core phase and a surrounding annular phase. Applying the long wave approximations to the basic equations and the boundary conditions for inviscid and incompressible fluids, simplified nonlinear equations are derived for large deformation of the jet. It is numerically shown for a doubly infinite jet that the core phase is periodically capsuled by the annular phase, whose profiles are largely affected by density ratios and velocity difference between the core and annular phases. On the other hand, for a semi-infinite jet emanating from a nozzle exit, breakup of the jet brings about encapsulation in the downstream, whose profile becomes more sensitive to input disturbances when the Weber number is small. For larger Weber number, however, the breakup profiles are almost the same as those in the doubly infinite jet. In order to see the validity of the present model, breakup profiles are also shown for the parameters used in the previous experiments.