Experimental study of the linear stability of a falling liquid film in the presence of a turbulent gas stream

Using the local electrical conductivity method, the parameters of the linear waves generated on the surface of a falling liquid film in the presence of a co- or counter-current gas stream are measured. The Reynolds numbers of the fluid and the gas were varied from 24 to 125 and from 0 to 8000, respectively. The results are presented in the form of dispersion relations. In the case of the absence of a gas stream, the results are compared with calculations based on a linear integral theory. It is shown that a gas stream increases the instability of the film and a counter-current gas flow has a greater effect on the wave phase velocity than a co-current flow.