| Autor: |
Coward, Adrian V., Hall, Philip |
| Zdroj: |
Theoretical and Computational Fluid Dynamics; November 1993, Vol. 5 Issue: 6 p269-289, 21p |
| Abstrakt: |
The interfacial stability of rotating core-annular flows is investigated. The linear and nonlinear effects are considered for the case when the annular region is very thin. Both asymptotic and numerical methods are used to solve the flow in the core and film regions which are coupled by a difference in viscosity and density. The long-time behavior of the fluid-fluid interface is determined by deriving its nonlinear evolution in the form of a modified Kuramoto-Sivashinsky equation. We obtain a generalization of this equation to three dimensions. The flows considered are applicable to a wide array of physical problems where liquid films are used to lubricate higher- or lower-viscosity core fluids, for which a concentric arrangement is desired. Linearized solutions show that the effects of density and viscosity stratification are crucial to the stability of the interface. Rotation generally destabilizes nonaxisymmetric disturbances to the interface, whereas the centripetal forces tend to stabilize flows in which the film contains the heavier fluid. Nonlinear effects allow finite-amplitude helically traveling waves to exist when the fluids have different viscosities. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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