Fluid motions induced by an electric current discharge

1972 ◽  
Vol 329 (1576) ◽  
pp. 71-81 ◽  
Keyword(s):  
Electromagnetic Field ◽  
Flow Field ◽  
Electric Current ◽  
Kinematic Viscosity ◽  
Conducting Fluid ◽  
Total Current ◽  
Fluid Density ◽  
Current Discharge ◽  
Monotonically Increasing Function ◽  
Increasing Function

In this paper we consider the flow field induced by an electric current discharge emerging from a small hole (mathematically a point) of a plane wall, bounding an incompressible viscous conducting fluid. The current is directed radially from the discharge. In earlier work, where the effect of the velocity on the electromagnetic field was neglected, it was shown that the velocity field contains singularities, and therefore the solution breaks down, when K = 2 J 2 0 / πρv 2 > K crit ≈ 300.1. Here J 0 is the total current of the discharge, ρ the fluid density and v the coefficient of kinematic viscosity. It is found that for a finitely conducting fluid when account is taken of the effect of the velocity on the electromagnetic field, K crit is a monotonically increasing function of α = 4 πvσ where σ is the electrical conductivity of the fluid. The interaction of this flow field with that due to a jet or sink of momentum, emerging from the same hole as the electric current discharge, is also considered in some detail.

On magnetohydrodynamic flows generated by an electric current discharge

1974 ◽  
Vol 63 (4) ◽  
pp. 665-671 ◽  
Author(s):  
C. Sozou
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
Electric Current ◽  
Critical Value ◽  
Conducting Fluid ◽  
Infinite Plane ◽  
Current Discharge ◽  
Practical Applications ◽  
Magnetohydrodynamic Flows ◽  
Theory And Experiment

Magnetohydrodynamic flows generated in a semi-infinite viscous incompressible conducting fluid by the discharge of an electric current J0 from a point on the infinite plane bounding the fluid develop singularities when J0 exceeds a certain critical value. In practical applications sometimes currents much in excess of the critical value of J0 may be passed between electrodes before singularities appear in the velocity field. In this paper we consider the flow field associated with some current distributions and attempt to provide an explanation for the discrepancy between theory and experiment.

On fluid motions induced by an electromagnetic field in a liquid drop immersed in a conducting fluid

1972 ◽  
Vol 51 (3) ◽  
pp. 585-591 ◽  
Author(s):  
C. Sozou
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Field ◽  
Flow Field ◽  
Electric Field ◽  
Lorentz Force ◽  
Liquid Drop ◽  
Conducting Fluid ◽  
Uniform Electric Field ◽  
Tangential Electric Field ◽  
Set Up

The deformation of a liquid drop immersed in a conducting fluid by the imposition of a uniform electric field is investigated. The flow field set up is due to the surface charge and the tangential electric field stress over the surface of the drop, and the rotationality of the Lorentz force which is set up by the electric current and the associated magnetic field. It is shown that when the fluids are poor conductors and good dielectrics the effects of the Lorentz force are minimal and the flow field is due to the stresses of the electric field tangential to the surface of the drop, in agreement with other authors. When, however, the fluids are highly conducting and poor dielectrics the effects of the Lorentz force may be predominant, especially for larger drops.

The development of magnetohydrodynamic flow due to an electric current discharge

1975 ◽  
Vol 70 (3) ◽  
pp. 509-517 ◽  
Author(s):  
C. Sozou ◽  
W. M. Pickering
Keyword(s):  
Flow Field ◽  
Electric Current ◽  
Stagnation Point ◽  
Cross Section ◽  
Kinematic Viscosity ◽  
Magnetohydrodynamic Flow ◽  
Dimensionless Variable ◽  
Closed Loops ◽  
Developing Flow ◽  
Set Up

The development of the magnetohydrodynamic flow field due to the discharge of an electric current J0 from a point on a plate bounding a semi-infinite viscous incompressible conducting fluid is considered. The flow field is the response of the fluid to the Lorentz force set up by the electric current and the associated magnetic field. The problem is formulated in terms of the dimensionless variable (vt)½/r and solved numerically. Here ν is the coefficient of kinematic viscosity, t the time from the application of the electric current and r the distance from the discharge. It is shown that the streamlines of the developing flow field in a cross-section through the axis of the discharge are closed loops about a stagnation point. As the flow field develops, the stagnation point moves to infinity along a ray emanating from the discharge with a speed proportional to t−½. The steady state, within a distance r from the discharge, is practically established when t = r2/ν.

Extinction in the Pigeon after Continuous Reinforcement: Effect of Number of Reinforced Responses

1971 ◽  
Vol 28 (1) ◽  
pp. 331-338 ◽  
Author(s):  
Laurel Furumoto
Keyword(s):  
Animal Studies ◽  
Food Pellet ◽  
Key Peck ◽  
Continuous Reinforcement ◽  
Gm Food ◽  
Free Operant ◽  
Time To Extinction ◽  
Monotonically Increasing Function ◽  
Increasing Functions ◽  
Increasing Function

Number of responses and time to extinction were measured after 3, 10, 1000, 3000, 5000, and 10,000 reinforced key-peck responses during conditioning. Each response was reinforced with a 045-gm. food pellet. The number of responses in extinction was a monotonically increasing function which became asymptotic beyond 1000 reinforced responses. Number of reinforced responses during conditioning significantly affected the number of responses in extinction ( p < .001) but not the time to extinction. The results support the findings of previous free-operant bar-press studies with rats. Free-operant animal studies of extinction after continuous reinforcement have consistently produced monotonically increasing functions and have typically employed relatively small amounts of reinforcement. Amount of reward may be an important parameter determining the shape of the extinction function in the free-operant studies.

Judgment of Temporal Duration of Stimulus Components in a Spatial Sequence

1973 ◽  
Vol 37 (2) ◽  
pp. 619-623
Author(s):  
Suchoon S. Mo ◽  
Michael D. Blaszcszack ◽  
Kathleen Ward
Keyword(s):  
Stimulus Presentation ◽  
Temporal Duration ◽  
Monotonically Increasing Function ◽  
Increasing Function

Judgment of the duration of the stimulus components of tri-grams consisting of consonants was a monotonically increasing function of the letter positions in the sequence of left to right. This tendency was more clearly demonstrated when the frequency of the stimulus presentation exceeded the frequency of the presentation of the stimulus components.

Thermodynamic Performance of an Actual Thermo-Acoustic Refrigeration Micro-Cycle

2012 ◽  
Vol 614-615 ◽  
pp. 64-68
Author(s):  
Tuo Wang ◽  
Feng Wu ◽  
Jin Hua Fei ◽  
Ming Fang Liu
Keyword(s):  
Coefficient Of Performance ◽  
Pressure Amplitude ◽  
Cooling Load ◽  
Acoustic Effect ◽  
Thermodynamic Performance ◽  
Monotonically Increasing Function ◽  
Analytic Expressions ◽  
New Type ◽  
The Relationship ◽  
Increasing Function

Thermo-acoustic refrigerator is a new type of engine, which is based on the thermo-acoustic effect. A new model which expresses as an ellipse in pressure-volume diagram is established to investigate the thermodynamic performance of an actual thermo-acoustic refrigeration micro-cycle. The demarcation points of endothermic processes and exothermic processes in the actual micro-cycle are found. The analytic expressions of the dimensionless cooling load and the coefficient of performance (COP) are deduced. The relationship between the dimensionless cooling load and the COP are investigated by numerical examples. The results show that the dimensionless cooling load is a monotonically increasing function of the COP and the pressure amplitude.

Magnetohydrodynamic flow due to the discharge of an electric current in a hemispherical container

1976 ◽  
Vol 73 (4) ◽  
pp. 641-650 ◽  
Author(s):  
C. Sozou ◽  
W. M. Pickering
Keyword(s):  
Free Surface ◽  
Velocity Field ◽  
Flow Field ◽  
Electric Current ◽  
Cross Section ◽  
Analytic Solution ◽  
Closed Loops ◽  
Slow Viscous Flow ◽  
Axial Cross Section ◽  
Section Form

In this paper we consider the flow field induced in an incompressible viscous conducting fluid in a hemispherical bowl by a symmetric discharge of electric current from a point source at the centre of the plane end of the hemisphere. This plane end is a free surface. We construct an analytic solution for the slow viscous flow and a numeriacl solution for the nonlinear problem. The streamlines in an axial cross-section form two sets of closed loops, one on either side of the axis. Our computations indicate that, for a given fluid, when the discharged current reaches a certain magnitude the velocity field breaks down. This breakdown probably originates at the vertex of the hemispherical container.

Full-Spectrum k-Distribution Model for Radiation in Gas Based on Multi-Group Methods

2014 ◽  
Vol 1008-1009 ◽  
pp. 839-845
Author(s):  
Yue Zhou ◽  
Qiang Wang ◽  
Hai Yang Hu
Keyword(s):  
Narrow Band ◽  
Wide Band ◽  
Distribution Model ◽  
Full Spectrum ◽  
Distribution Method ◽  
One Dimensional ◽  
Group Methods ◽  
Monotonically Increasing Function ◽  
Homogeneous Media ◽  
Increasing Function

The k-distribution method applied in narrow band and wide band is extended to the full spectrum based on spectroscopic datebase HITEMP, educing the full-spectrum k-distribution model. Absorption coefficents in this model are reordered into a smooth,monotonically increasing function such that the intensity calculations are performed only once for each absorption coefficent value and the resulting computations are immensely more efficent.Accuracy of this model is examined for cases ranging from homogeneous one-dimensional carbon dioxide to inhomogeneous ones with simultaneous variations in temperature. Comparision with line-by-line calculations (LBL) and narrow-band k-distribution (NBK) method as well as wide-band k-distribution (WBK) method shows that the full-spectrum k-distribution model is exact for homogeneous media, although the errors are greater than the other two models. After dividing the absorption coefficients into several groups according to their temperature dependence, the full-spectrum k-distribution model achieves line-by-line accuracy for gases inhomogeneous in temperature, accompanied by lower computational expense as compared to NBK model or WBK model. It is worth noting that a new grouping scheme is provided in this paper.

INTRINSIC MAGNETIZATION RELAXATION PROPERTIES OF Y1:2:3

1991 ◽  
Vol 05 (04) ◽  
pp. 277-284 ◽  
Author(s):  
Y.Y. XUE ◽  
Z.J. HUANG ◽  
L. GAO ◽  
P.H. HOR ◽  
R.L. MENG ◽  
...  
Keyword(s):  
High Temperature ◽  
Critical State ◽  
Flux Pinning ◽  
High Temperature Superconductors ◽  
Distribution Model ◽  
Magnetization Relaxation ◽  
Pinning Potential ◽  
Monotonically Increasing Function ◽  
Monotonically Decreasing Function ◽  
Increasing Function

The intrinsic magnetization relaxation rate R(T)≡dM(t, T)/d ln t and the pinning potential U0(T) have been determined for single crystalline and melt-textured YBa2Cu3O7 (Y1:2:3) high temperature superconductors of different sizes in their critical state. In contrast to previous reports, R(T) is a monotonically decreasing function and U0(T), deduced from R(T), a monotonically increasing function of temperature. The unusual temperature dependence of U0 is qualitatively explained in terms of a collective flux pinning. The U0-distribution model previously proposed for HTS’s is not consistent with certain experimental observations.

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