The stability of a condensate film moving under the effect of gravity and turbulent flow of vapor

The linear stability of a condensate film moving along a vertical isothermal plate under the effect of gravity and turbulent vapor flow is investigated. The cases of both cocurrent and countercurrent motion of phases are treated with regard for phase transformation. An analytical solution for the distribution of film thickness along the plate taking into account the film inertia is obtained using the integral method. A two-wave equation is deduced for the film thickness, and dispersion relations are derived. The effect of moving vapor on the film stability in a wide range of flow parameters is shown.