The dynamics of a droplet in a capillary constriction underwave excitation

The frequency dependence of the amplitude of the wave excitation mobilizing a droplet trapped in a capillary constriction is determined. The effect of droplet viscosity is analyzed. The problem of free longitudinal oscillations of a viscous-fluid droplet in a capillary constriction is considered. The influence of the surface tension, the droplet volume, and the constriction shape on the natural frequency of droplet longitudinal oscillations is studied. A formula for calculating the droplet natural frequency in the conical constriction is obtained and analyzed.