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The Shape and Stability of Wall-Bound and Wall-Edge-Bound Drops and Bubbles
Microgravity Science and Technology (2005)
  • Yongkang Chen
  • Mike Bacich
  • Cory L. Nardin
  • Albert Sitorus
  • Mark M. Weislogel, Portland State University
Abstract

The behavior of wall-bound drops and bubbles is fundamental to many natural and industrial processes. Key characteristics of such capillary systems include interface shape and stability for a variety of gravity levels and orientations. Significant solutions are in hand for axisymmetric pendent drops for a variety of uniform boundary conditions along the contact line with gravity acting normal to a planar wall. The special case of a wall-bound drop or bubble that is also pinned at an edge (i.e. a ‘wall-edge-bound’ drop) is considered here where numerical solutions are obtained for interface shape and stability as functions of drop volume, contact angle, fluid properties, and uniform gravity vector. For a semi-infinite zero-thickness planar wall (plate), a critical contact angle is identified below which wall-edge-bound drops are always stable. The critical contact angle is computed as a function of the gravity vector. The numerical procedure, which makes no account for contact angle hysteresis, predicts that such wall-edge-bound drops are unconditionally unstable for any gravity field with a component that is tangent to the wall while inwardly normal to the edge. Select experiments are conducted that support the conclusions drawn from the numerical results.

Disciplines
Publication Date
December, 2005
Citation Information
Yongkang Chen, Mike Bacich, Cory L. Nardin, Albert Sitorus, et al.. "The Shape and Stability of Wall-Bound and Wall-Edge-Bound Drops and Bubbles" Microgravity Science and Technology Vol. 17 Iss. 4 (2005)
Available at: http://works.bepress.com/mark_weislogel/19/