A theoretical study of the longitudinal motion of a vertical liquid jet

摘要

The breakup phenomena of a vertical laminar jet issuing from a capillary tube in quiescent ambient air are investigated. Using a linear approach to the transient jet velocity, an approximate equation for the longitudinal motion of a vertical liquid jet is theoretically derived. The instability analysis is performed by a vibration method since the form of the equation resembles that of the Rayleigh differential equation in a dynamic system. From the dimensionless one-dimensional model, there are effects of the disturbance velocity on the instability in a gravity-free environment. In contrast, the instability of the liquid column is more affected by the disturbance velocity and the Bond number in a gravity environment, which is verified by comparisons of the theoretical data with the experimental frequencies. However, the effects of the surface wave are considered to be dominant in the condition of the large magnitude of initial disturbances by forces such as forced vibration. [References: 14]