Instability of a Thin Liquid Jet with Near-Critical Mixing Surface under Micro-Gravity Condition. 2nd Report. Theoretical Consideration.

Abstract

The experimental results presented in the first report are physically interpreted on theoretical grounds to reveal the disintegration mechanism of the O(1)-Weber-number liquid jet with nearcritical mixing surface. The wavelength at which the liquid jet breaks up is much shorter than that of Rayleigh instability, suggesting that the shear layer developed on the near-critical mixing surface plays an important role in excitation of the instability. Vortex rings, which grows by Kelvin instability, entrain and impinge the surrounding dense gas on the contracting part of the liquid column, so that the restoring force associated with the axial surface tension is cancelled by the dynamic pressure of the impinging gas, and the liquid column breaks up by the action of contracting force due to the circumferential surface tension. This mechanism leads to a concept which bridges the Rayleigh type of atomization and the large-scale vortical structures of a supercritical liquid jet.