Experimental study of the effect of various surfactants on the wave characteristics of the film flow

Abstract

Abstract In this paper we present the results of experimental investigation of the effect of ionic surfactants (sodium dodecyl sulfate and cetrimonium bromide) at various concentrations on the vertical film flow in the range of Reynolds numbers 10 < Re < 50. The laser-induced fluorescence technique was used for instant film thickness measurements. The results are compared with data obtained for non-ionic Triton X-100. For all surfactants the rivulets formation and the dumping of wave motion are observed. The difference in the action of ionic and non-ionic surfactants on wave motion is revealed. Such deviations indicate that for ionic surfactants the surface tension relaxation process (at least in the case of film flows) is not fully described by diffusion processes, but has a more complex nature.