Because of the importance of falling liquid films in engineering applications such as evaporators, chemical reactors, condensers, turbine blades, etc., film flow and related problems have received considerable attention. Great augmentation in heat transfer can be expected for a vertical wall being wetted by a liquid film. So, a large body of literature was presented or published on the topic of transport characteristics of falling liquid film flow, especially in the last two decades. Chu and Dukler [1, 2] measured instantaneous thickness related to wavy liquid film flow in the situation of Re > 700. They stressed the random characteristics of film thickness variation with time and presented meaningful statistical analyses. They interpreted their data in terms of two main classes of random waves, i.e., large waves which carry a significant portion of all flowing liquid and small waves which cover the substrate that exists between large waves. They concluded that, the small wave structure controls the fluid resistance and transfer process in the gas while the large waves control these same processes in the liquid film. Recently, instantaneous film thickness and other parameters were studied experimentally for Re ranging from 30 to 5000 [3–5] , or studied numerically [6–9] . Several conclusions were reached as follows :