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The Influence of Dynamic Contact Angle on Wetting DynamicsWhen surface tension forces dominate, and regardless of whether the situation is static or dynamic, the contact angle (the angle the interface between two immiscible fluids makes when it contacts a solid) is the key parameter that determines the shape of a fluid-fluid interface. The static contact angle is easy to measure and implement in models predicting static capillary surface shapes and such associated quantities as pressure drops. By contrast, when the interface moves relative to the solid (as in dynamic wetting processes) the dynamic contact angle is not identified unambiguously because it depends on the geometry of the system Consequently, its determination becomes problematic and measurements in one geometry cannot be applied in another for prediction purposes. However, knowing how to measure and use the dynamic contact angle is crucial to determine such dynamics as a microsystem throughput reliably. In this talk we will present experimental and analytical efforts aimed at resolving modeling issues present in dynamic wetting. We will review experiments that show the inadequacy of the usual hydrodynamic model when a fluid-fluid meniscus moves over a solid surface such as the wall of a small tube or duct. We will then present analytical results that show how to parametrize these problems in a predictive manner. We will illustrate these ideas by showing how to implement the method in numerical fluid mechanical calculations.
Document ID
20050201793
Document Type
Preprint (Draft being sent to journal)
Authors
Rame, Enrique (NASA Glenn Research Center Cleveland, OH, United States)
Garoff, Steven (Carnegie-Mellon Univ. Pittsburgh, PA, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2005
Subject Category
Fluid Mechanics and Thermodynamics
Meeting Information
Lab Fusion 2004(Boston, MA)
Funding Number(s)
CONTRACT_GRANT: NCC-975
Distribution Limits
Public
Copyright
Other