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Stability of a charged drop near a conductor wall

DSpace at IIT Bombay

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Title Stability of a charged drop near a conductor wall
 
Creator MHATRE, SE
DESHMUKH, SD
THAOKAR, RM
 
Subject SOLID-SURFACE
DEFORMATION
BOUNDARY
FISSION
IMPACT
SPRAY
 
Description The effect of conductor boundaries on the deformation and stability of a charged drop is presented. The motivation for such a study is the occurrence of a charged conductor drop near a conductor wall in experiments (Millikan-like set-up in studies on Rayleigh break-up) and applications (such as electrospraying, ink-jet printing and ion mass spectroscopy). In the present work, analytical (linear stability analysis (LSA)) and numerical methods (boundary element method (BEM)) are used to understand the instability. Two kinds of boundaries are studied: a spherical, conducting, grounded enclosure (similar to a spherical capacitor) and a planar conducting wall. The LSA of a charged drop placed at the center of a spherical cavity shows that the Rayleigh critical charge (corresponding to the most unstable l = 2 Legendre mode) is reduced as the non-dimensional distance (d) over cap = b-a/a decreases, where a and b are the radii of the drop and spherical cavity, respectively. The critical charge is independent of the assumptions of constant charge or constant potential conditions. The trans-critical bifurcation diagram, constructed using BEM, shows that the prolate shapes are subcritically unstable over a much wider range of charge as (d) over cap decreases. The study is then extended to the stability of a charged conductor drop near a flat conductor wall. Analytical theory for this case is difficult and the stability as well as the bifurcation diagram are constructed using BEM. Moreover, the induced charges in the conductor wall lead to attraction of the drop to the wall, thereby making it difficult to conduct a systematic analysis. The drop is therefore assumed to be held at its position by an external force such as the electric field. The case when the applied field is much smaller than the field due to inherent charge on the drop (a(3)rho g/3e(0)psi(2)
 
Publisher SPRINGER
 
Date 2014-10-15T15:45:57Z
2014-10-15T15:45:57Z
2012
 
Type Article
 
Identifier EUROPEAN PHYSICAL JOURNAL E, 35(5)
http://dx.doi.org/10.1140/epje/i2012-12039-4
http://dspace.library.iitb.ac.in/jspui/handle/100/15188
 
Language en