STUDY ON ELECTROHYDRODYNAMIC CAPILLARY INSTABILITY OF VISCOELASTIC FLUIDS IN PRESENCE OF AXIAL ELECTRIC FIELD

2012 ◽  
Vol 04 (03) ◽  
pp. 1250027 ◽  
Author(s):  
D. K. TIWARI ◽  
MUKESH KUMAR AWASTHI ◽  
G. S. AGRAWAL
Keyword(s):  
Electric Field ◽  
Flow Analysis ◽  
Critical Value ◽  
Deborah Number ◽  
Wave Number ◽  
Conductivity Ratio ◽  
Ohnesorge Number ◽  
Capillary Instability ◽  
Axial Electric Field ◽  
Linear Viscoelastic

Linear viscoelastic potential flow analysis of capillary instability in presence of axial electric field has been studied. A dispersion relation is derived for the case of axially imposed electric field and stability is discussed in terms of various parameters such as electric field, Deborah number, Ohnesorge number, permittivity ratio and conductivity ratio etc. Stability criterion is given in the terms of critical value of wave number as well as critical value of applied electric field. The system is unstable when electric field is less than the critical value of electric field, otherwise it is stable. It has been found that in presence of the electric field the growth rates for viscoelastic fluid are higher than viscous fluid. Various graphs have been plotted for growth rate and critical electric field.

PRESSURE CORRECTIONS FOR THE VISCOELASTIC POTENTIAL FLOW ANALYSIS OF ELECTROHYDRODYNAMIC CAPILLARY INSTABILITY

2012 ◽  
Vol 04 (04) ◽  
pp. 1250047 ◽  
Author(s):  
MUKESH KUMAR AWASTHI ◽  
D. K. TIWARI ◽  
RISHI ASTHANA
Keyword(s):  
Electric Field ◽  
Normal Stress ◽  
Potential Flow ◽  
Flow Analysis ◽  
Critical Value ◽  
Deborah Number ◽  
Wave Number ◽  
Capillary Instability ◽  
Two Fluids ◽  
Viscous Pressure

Pressure corrections for the viscoelastic potential flow analysis of capillary instability in the presence of axial electric field has been carried out. In viscoelastic potential flow theory, viscosity enters through normal stress balance and the effects of shearing stresses are completely neglected. We include the viscous pressure in the normal stress balance along with irrotational pressure and it is assumed that this viscous pressure will resolve the discontinuity of the tangential stresses at the interface for two fluids. A dispersion relation is derived for the case of axially imposed electric field and stability is discussed in terms of various parameters such as electric field, Deborah number, Ohnesorge number, permittivity ratio and conductivity ratio etc. Stability criterion is given in terms of critical value of wave number as well as critical value of applied electric field. The system is unstable when electric field is less than the critical value of electric field, otherwise it is stable. It has been found that irrotational shearing stresses have stabilizing effect on the stability of the system.

STUDY ON ELECTROHYDRODYNAMIC CAPILLARY INSTABILITY OF VISCOELASTIC FLUIDS WITH RADIAL ELECTRIC FIELD

2014 ◽  
Vol 06 (04) ◽  
pp. 1450037
Author(s):  
MUKESH KUMAR AWASTHI
Keyword(s):  
Dispersion Relation ◽  
Electric Field ◽  
Radial Electric Field ◽  
Critical Value ◽  
Linear Analysis ◽  
Wave Number ◽  
Dual Effect ◽  
Capillary Instability ◽  
Viscous Potential Flow ◽  
The Stability

We study the linear analysis of electrohydrodynamic capillary instability of the interface between a viscous fluid and viscoelastic fluid of Maxwell type, when the phases are enclosed between two horizontal cylindrical surfaces coaxial with the interface, and when fluids are subjected to the radial electric field. Here, we use an irrotational theory known as viscous potential flow (VPF) theory in which viscosity enters through normal stress balance but shearing stresses are assumed to be zero. A quadratic dispersion relation that accounts for the growth of axisymmetric waves is obtained and stability criterion is given in terms of a critical value of wave number as well as electric field. It is observed that the radial electric field has dual effect on the stability of the system.

Effects of non-axial electric field gradients on the ferromagnetic state of amorphous rare-earth alloys

1980 ◽  
Vol 58 (5) ◽  
pp. 629-632 ◽  
Author(s):  
H. Hernandez ◽  
R. Ferrer ◽  
M. J. Zuckermann
Keyword(s):  
Rare Earth ◽  
Electric Field ◽  
Ferromagnetic State ◽  
Rare Earth Alloys ◽  
Electric Field Gradients ◽  
Axial Electric Field ◽  
Ferromagnetic Alloys ◽  
Field Gradients ◽  
Ordered State

We discuss the influence of non-axial electric field gradients on the ordered state of amorphous ferromagnetic alloys containing rare-earth atoms.

Numerical Simulations of Electric Field Driven Self-Assembly of Monolayers of Mixtures of Nanoparticles

2017 ◽  
Author(s):  
E. Amah ◽  
N. Musunuri ◽  
Ian S. Fischer ◽  
Pushpendra Singh
Keyword(s):  
Electric Field ◽  
Physical Properties ◽  
Numerical Simulations ◽  
Self Assembly ◽  
Composite Particle ◽  
Critical Value ◽  
Direct Numerical Simulations ◽  
Composite Particles ◽  
Liquid Interfaces ◽  
Induced Dipole

We numerically study the process of self-assembly of particle mixtures on fluid-liquid interfaces when an electric field is applied in the direction normal to the interface. The force law for the dependence of the electric field induced dipole-dipole and capillary forces on the distance between the particles and their physical properties obtained in an earlier study by performing direct numerical simulations is used for conducting simulations. The inter-particle forces cause mixtures of nanoparticles to self-assemble into molecular-like hierarchical arrangements consisting of composite particles which are organized in a pattern. However, there is a critical electric intensity value below which particles move under the influence of Brownian forces and do not self-assemble. Above the critical value, when the particles sizes differed by a factor of two or more, the composite particle has a larger particle at its core and several smaller particles forming a ring around it. Approximately same sized particles, when their concentrations are approximately equal, form binary particles or chains (analogous to polymeric molecules) in which positively and negatively polarized particles alternate, but when their concentrations differ the particles whose concentration is larger form rings around the particles with smaller concentration.

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