Capillary Electrodynamic Stability of Self-Gravitational Fluid Cylinder With Varying Electric Field

2012 ◽  
Vol 79 (2) ◽  
Author(s):  
Alfaisal A. Hasan
Keyword(s):  
Electric Field ◽  
Stability Criterion ◽  
Present Model ◽  
Transverse Electric ◽  
Combined Effect ◽  
Singular Solutions ◽  
Stabilizing Effect ◽  
Axisymmetric Perturbation ◽  
Small Domain ◽  
The Stability

The instability of a self-gravitating fluid cylinder surrounded by a self-gravitating tenuous medium pervaded by transverse varying electric field is discussed under the combined effect of the capillary, self-gravitating, and electric forces. This has been done for all axisymmetric and nonaxisymmetric modes of perturbation. The problem is formulated and solved with excluding the singular solutions, and the stability criterion is derived. Several published works are obtained as limiting cases from the present general case and investigated, and moreover the results are interpreted physically. The model is stable due to the stabilizing effect of the transverse electric field in all modes of perturbation. The destabilizing effect of the capillary and self-gravitating forces is found in small domain in the axisymmetric perturbation. However, the stabilizing effects of the capillary and self-gravitating forces in large axisymmetric domains and in all nonaxisymmetric domains modify and improve the instability of the present model.

scholarly journals Magnetohydrodynamic Stability of Streaming Jet Pervaded Internally by Varying Transverse Magnetic Field

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Alfaisal A. Hasan
Keyword(s):  
Magnetic Field ◽  
Numerical Analysis ◽  
Transverse Magnetic Field ◽  
Capillary Force ◽  
Present Model ◽  
Transverse Magnetic ◽  
Exterior Field ◽  
Stabilizing Effect ◽  
Basic Equations ◽  
The Stability

The Magnetohydrodynamic stability of a streaming cylindrical model penetrated by varying transverse magnetic field has been discussed. The problem is formulated, the basic equations are solved, upon appropriate boundary conditions the eigenvalue relation is derived and discussed analytically, and the results are verified numerically. The capillary force is destabilizing in a small axisymmetric domain and stabilizing otherwise. The streaming has a strong destabilizing effect in all kinds of perturbation. The toroidal varying magnetic field interior the fluid has no direct effect at all on the stability of the fluid column. The axial exterior field has strong stabilizing effect on the model. The effect of all acting forces altogether could be identified via the numerical analysis of the stability theory of the present model.

Study on Kelvin–Helmholtz Instability With Heat and Mass Transfer

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Mukesh Kumar Awasthi
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Stability Criterion ◽  
Relative Velocity ◽  
Critical Value ◽  
Helmholtz Instability ◽  
Stabilizing Effect ◽  
Vapor Fraction ◽  
The Stability ◽  
Liquid And Vapor Phases

The effect of heat and mass transfer on the Kelvin–Helmholtz instability between liquid and vapor phases of a fluid has been studied using three different theories: a purely irrotational theory based on the dissipation method, a hybrid irrotational-rotational theory, and an inviscid potential flow theory. These new results are compared with previous results from viscous irrotational theory. The stability criterion is given in terms of the critical value of relative velocity. The system is shown to be unstable when the relative velocity is greater than the critical value of relative velocity; otherwise, it is stable. It is observed that heat and mass transfer has a destabilizing effect on the stability of the system while vapor fraction has a stabilizing effect.

scholarly journals Electrohydrodynamic Interfacial Stability Conditions in the Presence of Heat and Mass Transfer and Oblique Electric Fields

1999 ◽  
Vol 54 (8-9) ◽  
pp. 470-476
Author(s):  
Mohamed Fahmy El-Sayed
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Electric Field ◽  
Heat And Mass Transfer ◽  
Electric Fields ◽  
Stability Criterion ◽  
Dielectric Constants ◽  
Interfacial Stability ◽  
Mass And Heat Transfer ◽  
The Stability

A novel mathematical formulation to deal with interfacial stability problems of the Kelvin-Helmholtz type with heat and mass transfer in the presence of oblique electric fields is presented. The perturbed system is composed of two homogeneous, inviscid, incompressible, dielectric, and streaming fluids sep-arated by a horizontal interface, and bounded by two rigid planes. The effect of a phase transition on the instability is considered, and the linear dispersion relations are obtained and discussed. It is found that the electric field has a major effect and can be chosen to stabilize or destabilize the flow. For Ray-leigh-Taylor instability problems of a liquid-vapor system it is found that the effect of mass and heat transfer enhances the stability of the system when the vapor is hotter than the liquid, although the clas-sical stability criterion is still valid. For Kelvin-Helmholtz instability problems, however, the classical stability criterion is found to be substantially modified due to the effects of the electric field, mass and heat transfer. A new stability condition relating the magnitude and orientation of the electric field and the dielectric constants is obtained. Oblique electric fields are found to have stabilizing effects which are reduced by the normal components of the electric fields. The effects of orientation of the electric fields and fluid depths on the stability configuration are also discussed.

scholarly journals The Development of the Atomic Theory of the Formation of a New Phase in Adsorbing Layers in an External Electric Field

2015 ◽  
Vol 16 (3) ◽  
pp. 520-523 ◽  
Author(s):  
E.Ph. Shtapenko ◽  
V.V. Tytarenko ◽  
V.A. Zabludovsky
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Nucleation Rate ◽  
Stability Criterion ◽  
Heterogeneous Nucleation ◽  
Atomic Theory ◽  
Adsorbed Layers ◽  
The Stability ◽  
Experimental Values ◽  
New Phase

The article deals with the nucleation rate in the development of the atomic theory. The expression for the calculation of heterogeneous nucleation rate in adsorbed layers in an external electric field, which allows for the stability criterion nucleus of a new phase. For example, the values of nickel electrocrystallisation nucleation rate in the development of the atomic theory and the classical theory of nucleation. A comparison with the experimental values. It is shown that at high overvoltage at the cathode developed atomic theory gives values of the nucleation rate closer to the experimental.

Scattering by a semi-infinite resistive strip of dominant-mode propagation in an infinite rectangular wave-guide

1956 ◽  
Vol 52 (3) ◽  
pp. 553-563 ◽  
Author(s):  
V. M. Papadopoulos
Keyword(s):  
Electric Field ◽  
Digital Computer ◽  
Transverse Electric ◽  
Dominant Mode ◽  
Surface Resistivity ◽  
Wave Guide ◽  
Mode Propagation ◽  
Rectangular Wave ◽  
Electric Mode ◽  
Transverse Electric Mode

ABSTRACTThe scattering of the dominant transverse electric mode in an infinite perfectly conducting rectangular wave-guide by a semi-infinite resistive strip, centrally placed and parallel to the electric field, is calculated by the use of Laplace transforms. Formulae are derived for the amplitude of the scattered waves, and the numerical results, obtained using a digital computer, are given for various values of the surface resistivity of the strip.

scholarly journals Stabilizing effect of methylcellulose on the dispersion of multi-walled carbon nanotubes in cementitious composites

2020 ◽  
Vol 9 (1) ◽  
pp. 93-104
Author(s):  
Mingrui Du ◽  
Yuan Gao ◽  
Guansheng Han ◽  
Luan Li ◽  
Hongwen Jing
Keyword(s):  
Carbon Nanotubes ◽  
Pore Solution ◽  
Cementitious Materials ◽  
High Ionic Strength ◽  
Cementitious Composites ◽  
Uniform Distributions ◽  
Stabilizing Effect ◽  
Multi Walled Carbon Nanotubes ◽  
The Stability ◽  
Walled Carbon Nanotubes

AbstractMulti-walled carbon nanotubes (MWCNTs) have been added in the plain cementitious materials to manufacture composites with the higher mechanical properties and smart behavior. The uniform distributions of MWCNTs is critical to obtain the desired enhancing effect, which, however, is challenged by the high ionic strength of the cement pore solution. Here, the effects of methylcellulose (MC) on stabilizing the dispersion of MWCNTs in the simulated cement pore solution and the viscosity of MWCNT suspensions werestudied. Further observations on the distributions of MWCNTs in the ternary cementitious composites were conducted. The results showed that MC forms a membranous envelope surrounding MWCNTs, which inhibits the adsorption of cations and maintains the steric repulsion between MWCNTs; thus, the stability of MWCNT dispersion in cement-based composites is improved. MC can also work as a viscosity adjuster that retards the Brownian mobility of MWCNTs, reducing their re-agglomerate within a period. MC with an addition ratio of 0.018 wt.% is suggested to achieve the optimum dispersion stabilizing effect. The findings here provide a way for stabilizing the other dispersed nano-additives in the cementitious composites.

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