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A singular minimization problem for droplet profiles

Published online by Cambridge University Press:  26 September 2008

Amy Novick-Cohen
Affiliation:
Department of Mathematics, Technion-Israel Institute of Technology, Haifa 32000, Israel

Abstract

A minimization problem for partially wetting droplet profiles is considered, in which Van der Waal's forces have been taken into account via a singular ‘disjoining pressure’. When the singular disjoining pressure is neglected, energy minimization leads to Laplace's equation and Young's equation; once the singular disjoining pressure is included, this is no longer the case. Indeed, the free energy is no longer bounded from below. Introducing the notion of overtaking to compare the energies of configurations whose energies are arbitrarily large and negative, we demonstrate that if a configuration is not convex then it cannot be an absolute minimizer. If profiles are allowed to ‘double-over’ then there does not exist an absolute minimizer. Within the class of profiles which do not double-over, absolute minimizers are shown to exist; these minimizing profiles are not single-valued. The singular minimization problem is shown to be discontinuously dependent on the definition of the wetting profile in the neighbourhood of the contact points; the implications of this discontinuity are discussed.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1993

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References

[1]Gauss, C. F. 1830 Principia Generalia Theoriae Figurae Fluidorum. Comment. Soc. Regiae Scient. Gottingensis Rec. 7. (Reprinted as ‘Grundlagen einer Theorie der Gestalt von Flussigkeiten im Zustand des Gleichgewichtes’, in Oswald's Klassiker des exakten Wissenschaften 135, Engelmann, Leipzig (1903) c vii 4, 15, 219.)Google Scholar
[2]De Gennes, P. G. 1985 Wetting: statistics and dynamics. Rev. Modern Phys. 57, 827863.Google Scholar
[3]Derjaguin, B. V., Churaev, N. V. & Muller, V. M. 1987 Surface Forces. Consultants Bureau, New York.Google Scholar
[4]Finn, R. 1986 Equilibrium Capillary Surfaces. Springer.CrossRefGoogle Scholar
[5]Novick-Cohen, A. 1992 On a minimization problem arising in wetting. SIAM Appl. Math. 52, 593613.CrossRefGoogle Scholar
[6]Gale, D. 1967 On optimal development in a multi-sector economy. Rev. Econ. Stud. 34, 119.CrossRefGoogle Scholar
[7]Von Weizsacker, C. C. 1965 Existence of optimal programs of accumulation for an infinite horizon. Rev. Econ. Stud. 32, 85104.CrossRefGoogle Scholar
[8]Giusti, E. 1984 Minimal Surfaces and Functions of Bounded Variation. Birkhäuser, Boston.CrossRefGoogle Scholar