1R36. Capillary Surfaces: Shape, Stability, Dynamics, in Particular Under Weightlessness. Tracts in Modern Physics, Vol 178. - D Langbein (Univ Bremen, Am Fallturm, Bremen, 28359, Germany). Springer-Verlag, Berlin. 2002. 364 pp. ISBN 3-540-41815-6. $219.00.
Reviewed by KJ Ruschak (Manuf Res and Eng Organization, Eastman Kodak, 2/35 Kodak Park, Rochester NY 14652-3701).
This book is a monograph on capillary hydrostatics and hydrodynamics treating liquid/air or liquid/liquid interfaces at small Bond number: a condition of near weightlessness, of nearly identical liquid densities, or of such small extent that surface energy effects dominate. Consideration is limited to pure liquids with constant and uniform surface tension. The book is predominantly theoretical and mathematical, but presents results for several experiments performed in spacecraft such as European Spacelab, in aircraft in parabolic flight, or in drop towers. Applications such as the design of liquid containers for spacecraft or the growth of large, high-quality crystals are mentioned, but not considered in detail. A solid background in the physics of capillary phenomena and in applied mathematics, including the calculus of variations, are requisites for the reader. The typically concise development at a high level makes the book unsuitable as a textbook or as an introduction to the subject matter.
The book primarily treats, usually from the perspective of minimization of free energy, equilibrium meniscus shapes and their stability according to the Gauss-Laplace (or Young-Laplace) differential equation of capillary hydrostatics. Stability is determined by variation of energy to verify a minimum or by the sufficient, but non-essential condition for instability of a minimum in volume as an independent parameter such as pressure is varied. The specific problems treated include liquid bridges between parallel plates that may be rotating; two liquid bridges between three colinear plates where the center plate floats between fixed-end plates; liquid shapes determined by wetting barriers arising from sharp edges or abrupt changes in the surface energy of the solid surface (canthotaxis or contact line pinning); partially filled containers of cylindrical and polygonal cross section; and menisci in wedges and corners. Some problems in capillary hydrodynamics, where pressure is modified by flow, are treated as well. These include flow into tubes and wedges driven by capillarity and the forced oscillation of liquid columns. Topics that are not covered in any depth include surfactants, non-ideal surfaces, dynamic contact angles, gradients in surface tension, and numerical methods of solution (although some results of numerical computations are presented).
The many photographs of static and dynamic menici from ingenious experiments conducted in spacecraft, aircraft, and drop towers are effective at stimulating interest. Nonetheless, the solid geometry, advanced mathematics, and typically concise development make for challenging reading.
The book has an extensive table of contents and four-page subject index. The last chapter is a listing of experiments, including those not directly related to the subject matter of the book, that have been conducted in sounding rockets, Spacelab, and satellites. The graphics are generally clear and effective, although some photographs are so small that interpretation is difficult, and some plots are so busy that individual curves are difficult to identify and track.
The author has produced an in-depth review and synthesis of results on the mathematical modeling of the equilibrium and dynamic shapes of menisci of pure liquids that have been observed experimentally under conditions of weightlessness. Readers interested in applications of this modeling or in physicochemical hydrodynamics will find the material limited. Capillary Surfaces: Shape, Stability, Dynamics, in Particular Under Weightlessness will be valuable to those working or having applications in this specialized area and useful as a reference to those with broader interests in capillary phenomena. The book is not recommended to those lacking significant background in fluid physics and applied mathematics.
