A theoretical and experimental study on the oscillation of a hanging drop

The damping oscillation of a hanging drop on a nozzle in the air was studied theoretically and experimentally. In the experiments, an elongated drop on a brass nozzle by electrostatic force was made to oscillate by removing the electric field instantaneously and the subsequent drop motion was recorded by a high-speed camera. In the theoretical study, the time-dependent drop shape and flow inside the drop were simulated numerically by use of the finite element method. It was found that the experimental results of oscillatory behavior for a hanging drop of aqueous glycerin solution were in good agreement with the calculated ones and that the frequency of oscillation was affected by drop volume, surface tension and nozzle size.