Hysteresis and non-uniqueness in the speed of the onset of instability in curtain coating

Marston, J.O. and Decent, S.P. and Simmons, M.J.H. (2006) Hysteresis and non-uniqueness in the speed of the onset of instability in curtain coating. Journal of Fluid Mechanics, 569. pp. 349-363. ISSN 0022-1120

Abstract

The maximum speed of stable coating is determined experimentally by the onset of air entrainment in curtain coating onto a pre-wetted surface over a broad range of dimensionless parameters (Reynolds number: 0.14<\it Re<33.02 ; capillary number: 0.19<\it Ca<25.07 ). We show not only that the substrate speed at the onset of instability is flow-rate dependent for a pre-wetted surface, but that the speed at which instability occurs is not always unique for a given flow rate.