Film flows over a spinning disk are applied to intensify heat and mass transfer processes, which need large contact surfaces between a liquid and surrounding gas. An inherent property of this flow is the formation of waves, whose amplitude may have the same scale as the film thickness. Experimental observations indicate a strong dependence of heat and mass transfer processes on these surface structures, especially in the case of large amplitude waves. This paper reports mathematical modelling of this flow. (C) 2003 Society of Chemical Industry.