A new predictive model for dual drops interactions has been formulated, covering four possible situations: namely coalescence, slip & separation, slip & conjunction and non-slip conjunction. The hydrodynamics and motion of a single drop or a conjunct drop rising in stagnant glycerol-water solutions were experimentally investigated. For Morton numbers ranging from 9.68x10(-3) to 51.40, the terminal rising velocities, the transverse oscillation frequencies and the wake of the conjunct drop are similar to those for a single drop with the same spherical-equivalent diameter. The rising velocities of a single drop and a conjunct drop were quantified on the basis of the expression for the drag coefficient and the feature size of the drops. The surrounding liquid flow fields for a single drop and a conjunct drop were measured by means of 2-D Particle Image Velocimetry, in order to identify the regions of the wake behind drops, and the similarities and differences between the flow fields were also discussed.