Formation of ribs on rotating rollers

Abstract

When thin films of liquid are produced by rolling it is commonly observed that the liquid film is not uniform but has regularly spaced thick lines or ribs. This phenomenon has been studied experimentally and it was found that the onset of ribbing was governed by the relation . At higher values of the parameter η/Sγ the number of ribs per centimetre increased sharply. At values of ηS/γ > 2·4 the rib number became independent of this parameter and varied solely with the geometrical parameters of the system, i.e. roller radius and gap.