A two-dimensional boundary layer model was established to describe the lateral flow of falling films driven by horizontal gas flow in the wave-plate channel based on boundary layer theory and independence assumption. The model reduction was presented through dimensionless analysis and ideal laminar flow assumption. The theoretical model was built to predict the films lateral migration and separation under the horizontal interface shear stress based on analytical force balance. The effects of wave-plate structure

both physical properties and flow conditions of gas-liquid were considered to give a critical separation criterion of the falling films along wave-plate. The criterion was compared with experimental measurements and some published theoretical models. The present model led to significantly better agreement with the experimental results and can be used to predict the breakdown of the films more accurately. Dimensionless analysis showed that inertial centrifugal force

shear stress

viscous force and surface tension controlled the movement

deformation and breakdown of liquid films

whose instability was associated with the equilibrium of these four forces.