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Oscillations of liquid captive rotating drops

Published online by Cambridge University Press:  26 April 2006

A. M. Gañán-Calvo
Affiliation:
Escuela Técnica Superior de Ingenieros Industrials, Universidad de Sevilla, 41012 Sevilla, Spain

Abstract

A linear analysis of the free oscillations of captive drops or bubbles is discussed. The drop is surrounded by an immiscible liquid or gas and undergoes rotation as a rigid body in the presence of gravity. Using spectral analytical methods, we provide a general formulation for both elliptic and hyperbolic oscillation regimes of the frequency spectrum, for any combination of the Weber and Bond numbers. The method uses a Green function to reduce the inviscid Navier–Stokes equations and boundary conditions to an eigenvalue problem. Both the Green function and normal velocities at the interface are expanded in the orthogonal functional space generated by the Sturm–Liouville problem associated to the interface equation. The effect on the vibration modes of the density and geometrical parameters of the captive drop and surrounding medium is analysed. We present a complete analysis of the low-frequency spectra in the elliptic regime of a set of floating liquid zones and captive drops for a continuous range of Weber and Bond numbers. It is shown that, depending on the geometrical parameters of the system, the elliptic vibration spectrum presents a sui generis modal interaction for low wavenumbers and certain ranges of Weber number.

Type
Research Article
Copyright
© 1991 Cambridge University Press

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References

Basaran, O. A. & Scriven, L. E., 1989 Axisymmetric shapes and stability of isolated charged drops. Phys. Fluids A 1 (5), 795798.Google Scholar
Boucher, E. A. & Evans, M. J. B. 1975 Pendant drop profiles and related capillary phenomena. Proc. R. Soc. Lond. 346, 349374.Google Scholar
Brown, R. A. & Scriven, L. E., 1980a The shape and stability of rotating liquid drops. Proc. R. Soc. Lond. 371, 331357.Google Scholar
Brown, R. A. & Scriven, L. E., 1980b The shape and stability of captive rotating drops. Phil. Trans. R. Soc. Lond. 259, 5179.Google Scholar
Busse, F. H.: 1984 Oscillations of a rotating liquid drop. J. Fluid Mech. 142. 18.Google Scholar
Butkov, E.: 1953 Mathematical Physics. Addison-Wesley.
Chifu, E., Stan, I., Finta, Z. & Gavrila, E., 1983 Marangoni-type surface flow on anunderformable free drop. J. Colloid Interface Sci. 93, 140150.Google Scholar
Gantán, A. & Barrero, A. 1986 Equilibrium shapes and free vibrations of liquid captive drops. In Physicochemical Hydrodynamics (ed. M. G. Velarde), pp. 5369. Plenum.
Gañán, A. & Barrero, A. 1990 Free oscillations of liquid captive drops. Microgravity Sci. Technol. III (2), 70–86.Google Scholar
Greenspan, H. P.: 1958 The Theory of Rotating Fluids. Cambridge University Press.
Gonzalez, H., Mccniskey, F. M. J., Castellanos, A. & Barrero, A., 1989 Stabilization of dielectric liquid bridges by electric fields in the absence of gravity. J. Fluid Mech. 206, 545561.Google Scholar
Lamb, H.: 1932 Hydrodynamics. Cambridge University Press.
Miller, C. A. & Scriven, L. E., 1953 The oscillations of a fluid droplet immersed in another fluid. J. Fluid Mech. 32, 417435.Google Scholar
Myshkis, A. D., Babskii, V. G., Kopachevskii, N. D., Slobozhanin, L. A. & Tyuptsov, A. D., 1987 Low-Gravity-Fluid Mechanics. Springer.
Padday, J. F.: 1971 The profiles of axially symmetric menisci. Phil. Trans. R. Soc. Lond. A 269, 265.Google Scholar
Pitts, E.: 1974 The stability of pendant liquid drops. Part 2. Axial symmetry. J. Fluid Mech. 63, 487508.Google Scholar
Pitts, E.: 1976 The stability of a drop hanging from a tube. J. Inst. Maths. Applies. 17, 387397.Google Scholar
Plateau, J.: 1873 Statique Expérimentale et Théorique des Liquides Soumis aux Seules Forces Moléculaires. Gauthier-Villars.
Rayleigh, Lokd 1945 The Theory of Sound. Dover.
Sanz, A.: 1985 The influence of the outer bath in the dynamics of axisymmetric liquid bridges. J. Fluid Mech. 156, 101140.Google Scholar
Sanz, A. & LópeZ Díez, J. 1989 Non-axisymmetric oscillations of liquid bridges. J. Fluid Mech. 205, 503521.Google Scholar
Steani, M. & Sabetta, F., 1984 Free vibrations of a drop in partial contact with a solid support. J. Fluid Mech. 141, 233247.Google Scholar
Strani, M. & Sabetta, F., 1988 Viscous oscillations of a supported drop in an immiscible fluid. J. Fluid Mech. 189, 397421.Google Scholar
Vega, J. M. & Perales, J. M., 1983 Almost cylindrical isorotating liquid bridges for small bond numbers. Proc. 4th European Symp. on Materials Sciences under Microgravity, Madrid, 1983. ESA SP-191. pp. 247252.Google Scholar