A stabilizing effect of vanishing diffusion in electrohydrodynamics

1997 ◽  
Vol 8 (2) ◽  
pp. 217-227
Author(s):  
EDUARD FEIREISL
Keyword(s):  
Weak Solution ◽  
Steady State ◽  
Electric Field ◽  
Diffusion Coefficients ◽  
Dielectric Liquid ◽  
Recombination Process ◽  
Homogeneous Steady State ◽  
Stabilizing Effect ◽  
Dc Electric Field ◽  
Spatially Homogeneous

We consider a model of the motion of a viscous dielectric liquid subjected to a DC electric field when the bulk conduction results from the presence of a dissociation-recombination process. It is shown that any weak solution approaches a neighbourhood of a spatially homogeneous steady state with radius r≈(d+ +d−)&14frac;, where d+, d− are the diffusion coefficients.

Breakup of a conducting drop in a uniform electric field

2014 ◽  
Vol 754 ◽  
pp. 550-589 ◽  
Author(s):  
Rahul B. Karyappa ◽  
Shivraj D. Deshmukh ◽  
Rochish M. Thaokar
Keyword(s):  
Steady State ◽  
Numerical Analysis ◽  
Electric Field ◽  
Viscosity Ratio ◽  
Uniform Electric Field ◽  
Shape Prior ◽  
Capillary Stress ◽  
Electric Stress ◽  
Dc Electric Field ◽  
Axisymmetric Shape

AbstractA conducting drop suspended in a viscous dielectric and subjected to a uniform DC electric field deforms to a steady-state shape when the electric stress and the viscous stress balance. Beyond a critical electric capillary number $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}\mathit{Ca}$, which is the ratio of the electric to the capillary stress, a drop undergoes breakup. Although the steady-state deformation is independent of the viscosity ratio $\lambda $ of the drop and the medium phase, the breakup itself is dependent upon $\lambda $ and $\mathit{Ca}$. We perform a detailed experimental and numerical analysis of the axisymmetric shape prior to breakup (ASPB), which explains that there are three different kinds of ASPB modes: the formation of lobes, pointed ends and non-pointed ends. The axisymmetric shapes undergo transformation into the non-axisymmetric shape at breakup (NASB) before disintegrating. It is found that the lobes, pointed ends and non-pointed ends observed in ASPB give way to NASB modes of charged lobes disintegration, regular jets (which can undergo a whipping instability) and open jets, respectively. A detailed experimental and numerical analysis of the ASPB modes is conducted that explains the origin of the experimentally observed NASB modes. Several interesting features are reported for each of the three axisymmetric and non-axisymmetric modes when a drop undergoes breakup.

High-speed isotachophoresis. Analytical aspects of the steady-state longitudinal temperature profiles

1979 ◽  
Vol 44 (3) ◽  
pp. 841-853 ◽  
Author(s):  
Zbyněk Ryšlavý ◽  
Petr Boček ◽  
Miroslav Deml ◽  
Jaroslav Janák
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Minor Component ◽  
Physical Models ◽  
Temperature Profiles ◽  
Longitudinal Temperature ◽  
Continuous Character

The problem of the longitudinal temperature distribution was solved and the bearing of the temperature profiles on the qualitative characteristics of the zones and on the interpretation of the record of the separation obtained from a universal detector was considered. Two approximative physical models were applied to the solution: in the first model, the temperature dependences of the mobilities are taken into account, the continuous character of the electric field intensity at the boundary being neglected; in the other model, the continuous character of the electric field intensity is allowed for. From a comparison of the two models it follows that in practice, the variations of the mobilities with the temperature are the principal factor affecting the shape of the temperature profiles, the assumption of a discontinuous jump of the electric field intensity at the boundary being a good approximation to the reality. It was deduced theoretically and verified experimentally that the longitudinal profiles can appreciably affect the longitudinal variation of the effective mobilities in the zone, with an infavourable influence upon the qualitative interpretation of the record. Pronounced effects can appear during the analyses of the minor components, where in the corresponding short zone a temperature distribution occurs due to the influence of the temperatures of the neighbouring zones such that the temperature in the zone of interest in fact does not attain a constant value in axial direction. The minor component does not possess the steady-state mobility throughout the zone, which makes the identification of the zone rather difficult.

Nonlinear photoacoustic effect of semiconductors in dc electric field

1990 ◽  
Vol 68 (8) ◽  
pp. 3865-3871 ◽  
Author(s):  
Jian‐chun Cheng ◽  
Shu‐yi Zhang ◽  
Yue‐sheng Lu
Keyword(s):  
Electric Field ◽  
Photoacoustic Effect ◽  
Dc Electric Field
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