THE STABILITY OF SUPERPOSED POLYMERIC FLUIDS FLOWING DOWN AN INCLINEDPLANE AND ITS APPLICATION TO COATING PROCESSES

Authors
Citation
Yy. Su, THE STABILITY OF SUPERPOSED POLYMERIC FLUIDS FLOWING DOWN AN INCLINEDPLANE AND ITS APPLICATION TO COATING PROCESSES, Polymer-plastics technology and engineering, 34(2), 1995, pp. 243-269
Citations number
13
Categorie Soggetti
Polymer Sciences
ISSN journal
03602559
Volume
34
Issue
2
Year of publication
1995
Pages
243 - 269
Database
ISI
SICI code
0360-2559(1995)34:2<243:TSOSPF>2.0.ZU;2-A
Abstract
A mathematical analysis has been performed to investigate the combined effects of viscosity and elasticity on the interfacial and the surfac e stabilities of two superposed Oldroyd-B fluids flowing down an incli ned plane. Our results indicate that arranging the less viscous and mo re elastic liquid as the skin layer is helpful in avoiding the occurre nce of interfacial waves. For the stability of free surface, it is fou nd that the elasticity in each layer is always destabilizing free surf ace waves. However, this destabilization can be lessened by designing the more viscous liquid as the skin layer. In addition, the effect of increasing Reynolds number on the interface and the free surface is in vestigated. It is shown that increasing Reynolds number can stabilize or destabilize the interface, depending on the parametric space of the now system. However, free surface is always destabilized by an increa se in Reynolds number. In general, our analysis indicates that under c ertain physical conditions (i.e., viscosity and elasticity ratios) and geometric conditions (i.e., depth ratio), stable operations in the co ating process can be attained.