In this paper, the movement of a gas-fluid flow in a plane channel with an oscillating wall was investigated. The aim of the research is to increase the efficiency of separation equipment by imposing the vibration impact on a gas-liquid flow. This purpose was achieved by applying the phenomenon of selective coagulation of a dropping liquid. The novelty of the proposed ap-proach concerns creating the mathematical model for determination of analytical dependences between the efficiency of the hydromechanical process and initial parameters of the separation device. As a result, quantitatively and qualitatively sufficient approximations for the scalar pres-sure and vector velocity fields were obtained with a permissible relative error in comparison with the results of numerical simulation. The presence of biharmonic fluctuation of particles was proved; besides, related dependencies for the calculation of vibration characteristics were ob-tained. Additionally, the paper presents the dependencies for identifying a range of thickness for a near-wall area. The system of dimensionless criteria was proposed for determining flow modes and relative trajectories of liquid droplets in a gas-fluid flow. The numerical simulation approach and related methodology of engineering calculations were proposed on the example of a plane channel of the separation device. Finally, the distance between adjacent zones of the pressure minimum was determined. As a result, it was found that this distance is equal to the wavelength of the vibrating impact to the flow that is an initial justification of further coagulation process of liquid droplets in a gas-liquid flow in a separation device
