Dynamics of a monodispersed drop cluster rising in another immiscible liquid in a presence of surfactant

The results of an experimental study of the rising process of a cluster of monodispersed drops of isoparaffin oil in a water-glycerol solution in the presence and absence of surfactant at the interface are presented. The cluster flow for the Reynolds numbers Re = 0.01–1 was studied. The effect of initial volume concentration of drops in a cluster on the rising dynamics was evaluated. New experimental data on drag coefficient for a cluster of monodispersed drops rising in a liquid with/without surfactant at the interface were obtained.