Determination of the dynamic surface tension of liquids from the instability of excited capillary jets and from the oscillation frequency of drops issued from such jets

Methods for measurement of the dynamic surface tension of liquids are developed, with emphasis on techniques applicable to the tension in surfaces of a lesser age (below one one-thousandth sec) than previously studied. Growth rates of axisymmetric disturbances on excited capillary jets and the oscillation frequency of drops issuing from excited capillary jets provide two techniques for assessing dynamic surface tension, as demonstrated by an experimental apparatus which stroboscopically illuminates the stream of drops from a capillary tube. Above the wavelength of maximum jet instability, the drops are found to resonate with the jet excitation frequency; an equivalence between the oscillation frequency of the drops and the resonance bandwidth in this wavelength domain provides a third means for dynamic surface tension determinations.