Magneto-gasdynamic flow over a wedge

1966 ◽  
Vol 25 (1) ◽  
pp. 165-178 ◽  
Author(s):  
D. C. Pack ◽  
G. W. Swan
Keyword(s):  
Magnetic Field ◽  
Shock Wave ◽  
Shock Waves ◽  
Wave Pattern ◽  
Ionized Gas ◽  
Current Sheets ◽  
Gasdynamic Flow ◽  
The Stability ◽  
The Magnetic Field ◽  
Insight Into

The solution for the flow of a fully ionized gas over a wedge of finite angle is known for the case when the applied magnetic field is aligned with the incident stream. In this flow there are current sheets on the surfaces of the wedge. When the magnetic field is allowed to deviate slightly from the stream, the current sheets may move into the gas and become shock waves. The magnetic fields adjacent to the wedge above and below it have to be matched. A perturbation method is introduced by means of which expressions for the unknown quantities in the different regions may be determined when there are four shocks attached to the wedge. The results give insight into the manner in which the shock-wave pattern develops as the obliquity of the magnetic field to the stream increases. The question of the stability of the shock waves is also examined.

scholarly journals Propagation of Shock Waves in a Polytrope with a Poloidal Magnetic Field

1968 ◽  
Vol 21 (5) ◽  
pp. 681
Author(s):  
Narendra K Sinha
Keyword(s):  
Magnetic Field ◽  
Shock Wave ◽  
Shock Waves ◽  
Poloidal Magnetic Field ◽  
The Magnetic Field

The propagation of a spherically developed shock wave in a poly trope with a poloida.l magnetic field has been studied using a generalization of Whitham's method. The effect of the magnetic field on the geometry of the front as well as on the effects brought about by the shock has been discussed.

Influence of Controlled Aggregation on Thermal Conductivity of Nanofluids

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Reza Azizian ◽  
Elham Doroodchi ◽  
Behdad Moghtaderi
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Ph Value ◽  
Mixture Theory ◽  
Aggregate Size ◽  
Growth Direction ◽  
The Stability ◽  
Induced Aggregation ◽  
The Magnetic Field ◽  
Insight Into

Nanoparticles aggregation is considered, by the heat transfer community, as one of the main factors responsible for the observed enhancement in the thermal conductivity of nanofluids. To gain a better insight into the veracity of this claim, we experimentally investigated the influence of nanoparticles aggregation induced by changing the pH value or imposing a magnetic field on the thermal conductivity of water-based nanofluids. The results showed that the enhancement in thermal conductivity of TiO2–water nanofluid, due to pH-induced aggregation of TiO2 nanoparticles, fell within the ±10% of the mixture theory, while applying an external magnetic force on Fe3O4–water nanofluid led to thermal conductivity enhancements of up to 167%. It is believed that the observed low enhancement in thermal conductivity of TiO2–water nanofluid is because, near the isoelectric point (IEP), the nanoparticles could settle out of the suspension in the form of large aggregates making the suspension rather unstable. The magnetic field however could provide a finer control over the aggregate size and growth direction without compromising the stability of the nanofluid, and hence significantly enhancing the thermal conductivity of the nanofluid.

Evolutionary conditions for shock waves in collisionless plasma and stability of the associated flow

1968 ◽  
Vol 2 (3) ◽  
pp. 449-463 ◽  
Author(s):  
Shigeki Morioka ◽  
John R. Spreiter
Keyword(s):  
Magnetic Field ◽  
Shock Wave ◽  
Heat Flux ◽  
Mach Number ◽  
Shock Waves ◽  
Strong Magnetic Field ◽  
Collisionless Plasma ◽  
Shock Stability ◽  
The Magnetic Field ◽  
Evolutionary Condition

The evolutionary condition for transverse and normal shock waves, and the fire- hose and mirror instability conditions for the associated flow, in a collisionless, anisotropic plasma having a strong magnetic field are determined using the theoretical representation of Chew, Goldberger & Low (1956) for such a medium. The results are expressed in terms of the Mach number, Alfvén Mach number, and the ratio of the temperatures parallel and perpendicular to the magnetic field in the flow approaching the shock wave, and applied to ascertain in what range of these parameters various types of instabilities may occur. The effect of the heat flux, which does not vanish generally in a collisionless plasma, on the shock stability is discussed.

Stability of magnetohydrodynamic shock waves

1967 ◽  
Vol 1 (4) ◽  
pp. 463-472 ◽  
Author(s):  
Martin Lessen ◽  
Narayan V. Deshpande
Keyword(s):  
Magnetic Field ◽  
Mach Number ◽  
Shock Waves ◽  
Growth Rates ◽  
Acoustic Waves ◽  
Normal Mode Analysis ◽  
Mode Analysis ◽  
Magnetohydrodynamic Shock ◽  
The Stability ◽  
The Magnetic Field

The stability of oblique magnetohycirodynamic shock waves is studied with respect to a disturbance that excites magneto-acoustic waves. The problem is solved numerically by the normal mode analysis and it is shown that slow shocks are unstable in the sense that the disturbance grows exponentially with time. Growth rates are calculated for a particular Mach number and for different values of the magnetic field and obliqueness. The fast shock appears to be stable.

Switch-shock wave structure in a magnetized partly-ionized gas

1975 ◽  
Vol 14 (2) ◽  
pp. 333-346 ◽  
Author(s):  
N. F. Cramer
Keyword(s):  
Magnetic Field ◽  
Shock Wave ◽  
Wave Structure ◽  
High Resistivity ◽  
Shock Wave Structure ◽  
Ionized Gas ◽  
Heavy Particles ◽  
Neutral Gas ◽  
Shock Transition ◽  
The Magnetic Field

The effect of the interaction of plasma and neutral gas on the structure of switchtype shock waves propagating in a partly-ionized gas is studied. These shocks, in which the magnetic field is perpendicular to the shock front either upstream or downstream, exhibit a spiralling behaviour of the magnetic field in the shock transition region, if the Hall term is important in the Ohm's law. Observation of this behaviour for shocks propagating into a plasma with a residual neutral content of ~ 15 % has implied an anomalously high resistivity of the plasma. We show that this can be partly explained by considering the collisions of ions with the neutral atoms in a magnetic field. We show that the extra dissipation due to the increase in resistivity goes primarily to the ions and neutrals. Thus even in the absence of viscous dissipation within each species, the heavy particles can be appreciably heated in a shock propagating into a partly-ionized gas in a magnetic field.

scholarly journals No-z Model for Magnetic Fields of Different Astrophysical Objects and Stability of the Solutions

Data ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 4
Author(s):  
Evgeny Mikhailov ◽  
Daniela Boneva ◽  
Maria Pashentseva
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Large Scale ◽  
Point Of View ◽  
Accretion Discs ◽  
Wide Range ◽  
Astrophysical Objects ◽  
Alpha Effect ◽  
The Stability ◽  
The Magnetic Field

A wide range of astrophysical objects, such as the Sun, galaxies, stars, planets, accretion discs etc., have large-scale magnetic fields. Their generation is often based on the dynamo mechanism, which is connected with joint action of the alpha-effect and differential rotation. They compete with the turbulent diffusion. If the dynamo is intensive enough, the magnetic field grows, else it decays. The magnetic field evolution is described by Steenbeck—Krause—Raedler equations, which are quite difficult to be solved. So, for different objects, specific two-dimensional models are used. As for thin discs (this shape corresponds to galaxies and accretion discs), usually, no-z approximation is used. Some of the partial derivatives are changed by the algebraic expressions, and the solenoidality condition is taken into account as well. The field generation is restricted by the equipartition value and saturates if the field becomes comparable with it. From the point of view of mathematical physics, they can be characterized as stable points of the equations. The field can come to these values monotonously or have oscillations. It depends on the type of the stability of these points, whether it is a node or focus. Here, we study the stability of such points and give examples for astrophysical applications.

scholarly journals Equation of state studies at SILP by laser-driven shock waves

1996 ◽  
Vol 14 (2) ◽  
pp. 157-169 ◽  
Author(s):  
Yuan Gu ◽  
Sizu Fu ◽  
Jiang Wu ◽  
Songyu Yu ◽  
Yuanlong Ni ◽  
...  
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Equation Of State ◽  
Shock Waves ◽  
Target Surface ◽  
Shock Adiabats ◽  
Pressure Shock ◽  
Aluminum Target ◽  
Laser Illumination ◽  
The Stability

The experimental progress of laser equation of state (EOS) studies at Shanghai Institute of Laser Plasma (SILP) is discussed in this paper. With a unique focal system, the uniformity of the laser illumination on the target surface is improved and a laser-driven shock wave with good spatial planarity is obtained. With an inclined aluminum target plane, the stability of shock waves are studied, and the corresponding thickness range of the target of laser-driven shock waves propagating steadily are given. The shock adiabats of Cu, Fe, SiO2 are experimentally measured. The pressure in the material is heightened remarkably with the flyer increasing pressure, and the effect of the increasing pressure is observed. Also, the high-pressure shock wave is produced and recorded in the experimentation of indirect laser-driven shock waves with the hohlraum target.

Magnetorheological fluid based on amorphous Fe-Si-B alloy magnetic particles

2021 ◽  
pp. 1045389X2110643
Author(s):  
Chuncheng Yang ◽  
Zhong Liu ◽  
Xiangyu Pei ◽  
Cuiling Jin ◽  
Mengchun Yu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Rheological Property ◽  
Magnetic Particles ◽  
Annealing Treatment ◽  
Magnetorheological Fluid ◽  
The Stability ◽  
The Magnetic Field ◽  
Amorphous Particle ◽  
Better Than

Magnetorheological fluids (MRFs) based on amorphous Fe-Si-B alloy magnetic particles were prepared. The influence of annealing treatment on stability and rheological property of MRFs was investigated. The saturation magnetization ( Ms) of amorphous Fe-Si-B particles after annealing at 550°C is 131.5 emu/g, which is higher than that of amorphous Fe-Si-B particles without annealing. Moreover, the stability of MRF with annealed amorphous Fe-Si-B particles is better than that of MRF without annealed amorphous Fe-Si-B particles. Stearic acid at 3 wt% was added to the MRF2 to enhance the fluid stability to greater than 90%. In addition, the rheological properties demonstrate that the prepared amorphous particle MRF shows relatively strong magnetic responsiveness, especially when the magnetic field strength reaches 365 kA/m. As the magnetic field intensified, the yield stress increased dramatically and followed the Herschel-Bulkley model.

The stability of viscous flow in a curved channel in the presence of a magnetic field

1961 ◽  
Vol 264 (1317) ◽  
pp. 155-164 ◽  
Keyword(s):  
Magnetic Field ◽  
Viscous Flow ◽  
Uniform Magnetic Field ◽  
Axial Direction ◽  
Electrical Conductor ◽  
Curved Channel ◽  
Coaxial Cylinders ◽  
Transverse Pressure ◽  
The Stability ◽  
The Magnetic Field

The stability of viscous flow between two coaxial cylinders maintained by a constant transverse pressure gradient is considered when the fluid is an electrical conductor and a uniform magnetic field is impressed in the axial direction. The problem is solved and the dependence of the critical number for the onset of instability on the strength of the magnetic field and the coefficient of electrical conductivity of the fluid is determined.

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