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Spatial modes of capillary jets, with application to surface stimulation

Published online by Cambridge University Press:  16 May 2012

J. Guerrero
Affiliation:
Departamento de Física Aplicada III, Escuela Técnica Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos, s/n 41092-Sevilla, Spain Group of Electrohydrodynamics and Cohesive Granular Media, Facultad de Física, Universidad de Sevilla, Avenida Reina Mercedes, s/n. 41012-Sevilla, Spain
H. González*
Affiliation:
Departamento de Física Aplicada III, Escuela Técnica Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos, s/n 41092-Sevilla, Spain Group of Electrohydrodynamics and Cohesive Granular Media, Facultad de Física, Universidad de Sevilla, Avenida Reina Mercedes, s/n. 41012-Sevilla, Spain
F. J. García
Affiliation:
Departamento de Física Aplicada I, Escuela Técnica Superior de Ingeniería Informática, Universidad de Sevilla, Avenida Reina Mercedes, s/n. 41012-Sevilla, Spain Group of Electrohydrodynamics and Cohesive Granular Media, Facultad de Física, Universidad de Sevilla, Avenida Reina Mercedes, s/n. 41012-Sevilla, Spain
*
Email address for correspondence: [email protected]

Abstract

Surface stimulation of any physical origin (electrohydrodynamic, thermocapillary, etc.) has the goal of generating localized perturbations on the free surface or the velocity field of a capillary jet. Among these perturbations, only the axisymmetric ones are determinant for the jet breakup. Often, the stimulation is weak enough for a linear model to be applicable. Then, the stimulation can be described by means of the Green functions for stresses, both normal and tangential to the interface, the calculations of which are, in addition, uncoupled from the hydrodynamic variables. If a harmonic forcing is applied, these Green functions are combinations of the spatial modes whose associated poles lie inside the appropriate integration contour of the complex wavenumber plane. This is the motivation for a comprehensive enumeration and description of the spatial modes, which has not been done up to now. Modes familiar from a temporal analysis, the dominant and subdominant capillary modes and the hydrodynamic modes, are present, along with modes specific to a spatial analysis. Most of the latter have already been mentioned in the literature for inviscid jets, but not analysed. A mode not previously found is reported. In addition, a description of the velocity field associated with each mode is provided, as a tool to understand their physical origin and behaviour. The relative importance of each mode in both normal- and tangential-stress stimulations is discussed. Finally, the well-known merging of poles below a critical jet velocity, leading to absolute instability, is analysed in the light of the modal description.

Type
Papers
Copyright
Copyright © Cambridge University Press 2012

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References

1. Ashpis, D. E. & Reshotko, E. 1990 The vibrating ribbon problem revisited. J. Fluid Mech. 213, 531547.Google Scholar
2. Awati, K. M. & Howes, T. 1996 Stationary waves on cylindrical fluid jets. Am. J. Phys. 64, 808811.CrossRefGoogle Scholar
3. Barbet, B. 1997 Stimulations électrohydrodynamique et thermique de jets de liquide conducteur. PhD thesis, Université Joseph Fourier, Grenoble 1, France.Google Scholar
4. Bers, A. 1983 Space time evolution of plasma instabilities. In Handbook of Plasma Physics, pp. 451517. North Holland.Google Scholar
5. Bogy, D. B. 1978 Wave propagation and instability of a circular semi-infinite liquid jet harmonically forced at the nozzle. Trans. ASME: J. Appl. Mech. 45, 469474.Google Scholar
6. Briggs, R. J. 1964 Electron Stream Interaction with Plasmas. MIT Press.Google Scholar
7. Busker, D. P. & Lamers, A. P. G. G. 1989 The nonlinear breakup of an inviscid liquid jet. Fluid Dyn. Res. 5, 159172.Google Scholar
8. Chandrasekhar, S. 1961 Hydrodynamic and Hydromagnetic Stability. Oxford University Press.Google Scholar
9. Crowley, J. M. 1983 Electrohydrodynamic droplet generators. J. Electrostat. 14, 121134.CrossRefGoogle Scholar
10. Crowley, J. M. 1986 Phased exciter arrays for EHD drop generators. IEEE Trans. Ind. Applics. 22 (6), 973976.Google Scholar
11. Eggers, J. 1997 Nonlinear dynamics and breakup of free-surface flows. Rev. Mod. Phys. 69 (3), 865929.CrossRefGoogle Scholar
12. Eggers, J. & Villermaux, E. 2008 Physics of liquid jets. Rep. Prog. Phys. 71, 179.Google Scholar
13. García, F. J. & González, H. 2008 Normal-mode linear analysis and initial conditions of capillary jets. J. Fluid Mech. 602, 81117.Google Scholar
14. Goedde, E. F. & Yuen, M. C. 1970 Experiments on liquid jet instability. J. Fluid Mech. 40, 495511.Google Scholar
15. González, H. & García, F. J. 2009 The measurement of growth rates in capillary jets. J. Fluid Mech. 619, 179212.CrossRefGoogle Scholar
16. Gordillo, J. M. & Pérez-Saborid, M. 2002 Transient effects in the signaling problem. Phys. Fluids 14 (12), 43294343.CrossRefGoogle Scholar
17. Gordillo, J. M. & Pérez-Saborid, M. 2005 Aerodynamic effects in the break-up of liquid jets: on the first wind-induced break-up regime. J. Fluid Mech. 541, 120.Google Scholar
18. Guerrero, J. 2011 Aplicación de campos eléctricos a chorros capilares. PhD thesis, Universidad de Sevilla, Sevilla, Spain.Google Scholar
19. Hancock, M. J. & Bush, J. W. M. 2002 Fluid pipes. J. Fluid Mech. 466, 285304.Google Scholar
20. Huerre, P. & Monkewitz, P. A. 1985 Absolute and convective instabilities in free shear layers. J. Fluid Mech. 59, 151168.Google Scholar
21. Huerre, P. & Monkewitz, P. A. 1990 Local and global instabilities in spatially developing flows. Annu. Rev. Fluid Mech. 22, 473537.CrossRefGoogle Scholar
22. Johnson, T. & Tucker, W. 2009 Enclosing all zeros of an analytic function: a rigourous approach. J. Comput. Appl. Maths 228, 418423.CrossRefGoogle Scholar
23. Keller, J. B., Rubinow, S. I. & Tu, Y. O. 1973 Spatial instability of a jet. Phys. Fluids 16 (12), 20522055.Google Scholar
24. Lamb, H. 1932 Hydrodynamics, 6th edn. Cambridge University Press.Google Scholar
25. Le Dizès, S. 1997 Global modes in falling capillary jets. Eur. J. Mech. (B/Fluids) 16 (6), 761778.Google Scholar
26. Lee, E. R. 2003 Microdrop Generation. CRC.Google Scholar
27. Leib, S. J. & Goldstein, M. E. 1986a The generation of capillary instabilities on a liquid jet. J. Fluid Mech. 168, 479500.Google Scholar
28. Leib, S. J. & Goldstein, M. E. 1986b Convective and absolute instability of a viscous jet. Phys. Fluids 29, 952954.CrossRefGoogle Scholar
29. Lin, S. P. 2003 Breakup of Liquid Sheets and Jets. Cambridge University Press.Google Scholar
30. Melcher, J. R. 1963 Field-Coupled Surface Waves. MIT Press.Google Scholar
31. Nahas, N. & Panton, R. 1990 Control of surface tension flows: instability of a liquid jet. Trans. ASME: J. Fluids Engng 112, 296301.Google Scholar
32. Nicolás, J. A. & Vega, J. M. 2000 Linear oscillations of axisymmetric viscous liquid bridges. Z. Angew. Math. Phys. 51, 701731.Google Scholar
33. Plateau, J. 1873 Statique Expérimentale et Théorique des Liquides Soumis aux Seules Forces Moléculaires. Gauthier Villars.Google Scholar
34. Rayleigh, Lord 1945 The Theory of Sound, 2nd edn, vol. II. Dover.Google Scholar
35. Sevilla, A. 2011 The effect of viscous relaxation on the spatiotemporal stability of capillary jets. J. Fluid Mech. 684, 204226.CrossRefGoogle Scholar
36. Spohn, A. & Atten, P. 1993 EHD multi-electrode stimulation of a conducting capillary jet. IEEE IAS Annual Meeting, 19601965.Google Scholar
37. Titchmarsh, E. C. 1939 The Theory of Functions. Oxford University Press.Google Scholar
38. Yakubenko, P. A. 1997 Capillary instability of an ideal jet of large but finite length. Eur. J. Mech. (B/Fluids) 16 (1), 3947.Google Scholar