Abstract
Nonlinear behavior of an annular viscous liquid jet is analytically examined. By means of the membrane approximation, a set of axisymmetric nonlinear equations is derived for the annular sheet with finite thickness when the surroundings are ignored. Preliminary linear analysis shows that the temporal growth rate of disturbances decreases as the viscosity increases, while the wavenumber region for the instability is left unchanged. It is found in the numerical analysis that the jet collapses through the sealing-off by closing of the annular part rather than the disintegration of the part when the viscosity increases. It is also found that the viscosity of the liquid not only delays the breakup, but also strongly affects the jet profiles in the vicinity of the collapse, for which some similarity is found in the renornialized annular radii.
