Spatial evolution of a film flowing down a fiber

We report the response to a forcing at the inlet of a film flowing down a vertical fiber. Parameters are chosen in order to examine the effects of both inertia and surface tension. The spatial response of the film to inlet forcing depends on the ratio of the forcing frequency ffor to the frequency fM corresponding to the maximum linear growth rate. At ffor≈fM, the primary instability leads directly to the formation of a saturated wavetrain at the forcing frequency, whereas at low forcing frequencies ffor