scholarly journals Magnetogasdynamic Shock Waves in a Rotating Gas with Exponentially Varying Density

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
J. P. Vishwakarma ◽  
G. Nath
Keyword(s):  
Magnetic Field ◽  
Shock Wave ◽  
Ambient Medium ◽  
Variable Velocity ◽  
Perfect Gas ◽  
Azimuthal Magnetic Field ◽  
One Dimensional ◽  
Adiabatic Flow ◽  
Exponential Law ◽  
Nonsimilar Solutions

Nonsimilar solutions are obtained for one-dimensional adiabatic flow behind a magnetogasdynamic cylindrical shock wave propagating in a rotating or nonrotating perfect gas in presence of a constant azimuthal magnetic field. The density of the gas is assumed to be varying and obeying an exponential law. In order to obtain the solutions, the angular velocity of the ambient medium is assumed to be decreasing exponentially as the distance from the axis increases. The shock wave moves with variable velocity and the total energy of the wave is nonconstant. The effects of variation of Alfven-Mach number and time are obtained. Also, a comparison between the solutions in the cases of rotating and non-rotating media with or without magnetic field is made.

scholarly journals A Self-Similar Flow behind a Magnetogasdynamic Shock Wave Generated by a Moving Piston in a Gravitating Gas with Variable Density: Isothermal Flow

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
G. Nath ◽  
A. K. Sinha
Keyword(s):  
Magnetic Field ◽  
Shock Wave ◽  
Ambient Medium ◽  
Initial Density ◽  
Power Laws ◽  
Variable Density ◽  
Ideal Gas ◽  
Piston Velocity ◽  
Azimuthal Magnetic Field ◽  
Initial Magnetic Field

The propagation of a cylindrical (or spherical) shock wave in an ideal gas with azimuthal magnetic field and with or without self-gravitational effects is investigated. The shock wave is driven out by a piston moving with time according to power law. The initial density and the initial magnetic field of the ambient medium are assumed to be varying and obeying power laws. Solutions are obtained, when the flow between the shock and the piston is isothermal. The gas is assumed to have infinite electrical conductivity. The shock wave moves with variable velocity, and the total energy of the wave is nonconstant. The effects of variation of the piston velocity exponent (i.e., variation of the initial density exponent), the initial magnetic field exponent, the gravitational parameter, and the Alfven-Mach number on the flow field are obtained. It is investigated that the self-gravitation reduces the effects of the magnetic field. A comparison is also made between gravitating and nongravitating cases.

Cylindrical shock wave in a self-gravitating perfect gas with azimuthal magnetic field via Lie group invariance method

2020 ◽  
Vol 17 (10) ◽  
pp. 2050148
Author(s):  
G. Nath ◽  
Arti Devi
Keyword(s):  
Magnetic Field ◽  
Shock Wave ◽  
Initial Density ◽  
Density Variation ◽  
Shock Strength ◽  
Adiabatic Exponent ◽  
Perfect Gas ◽  
Azimuthal Magnetic Field ◽  
Cylindrical Shock Wave ◽  
Variation Index

In this paper, we have studied the propagation of cylindrical shock waves in a self-gravitating perfect gas under the influence of azimuthal magnetic field. The method of Lie group invariance is used to construct some special class of self-similar solutions in the presence of the azimuthal magnetic field. The different cases of solutions with a power law and exponential law shock paths are obtained with the choice of arbitrary constants appearing in the expressions for the infinitesimal generators. The similarity solution for cylindrical shock wave with power law shock path is discussed in detail. The effects of variation of Alfven-Mach number, gravitation parameter, initial density variation index and adiabatic exponent on the flow variables are analyzed graphically. It is obtained that the increase in the values of Alfven-Mach number, gravitation parameter and adiabatic exponent have decaying effect on the shock strength. Also, the shock strength increases with an increase in the values of initial density variation index. A comparison is also made between the solutions in gravitating and non-gravitating cases in the presence of magnetic field.

One-dimensional adiabatic flow of equilibrium gas–particle mixtures in long vertical ducts with friction

1989 ◽  
Vol 203 ◽  
pp. 251-272 ◽  
Author(s):  
Guido Buresti ◽  
Claudio Casarosa
Keyword(s):  
Equilibrium Mixture ◽  
Adiabatic Heating ◽  
Explosive Eruptions ◽  
Perfect Gas ◽  
Typical Application ◽  
One Dimensional ◽  
Adiabatic Flow ◽  
Flow Parameters ◽  
Constant Area ◽  
Inlet Conditions

The equations of the steady, adiabatic, one-dimensional flow of an equilibrium mixture of a perfect gas and incompressible particles, in constant-area ducts with friction, are derived taking into account the effects of gravity and of the finite volume of the particles. As is the case for a pure gas, the mixture is shown to be subject to the phenomenon of choking, and the possibility of an adiabatic heating of the mixture in a subsonic expansion is also theoretically predicted for certain flow inlet conditions. The model may be used to approximately describe the conditions existing in portions of volcanic conduits during the Plinian phases of explosive eruptions. Some results of the numerical integration of the equations for a typical application of this type are briefly discussed, thus showing the potential of the model for carrying out rapid analyses of the influence of the main geometrical and flow parameters describing the problem. A non-volcanological application is also analysed to illustrate the possibility of the adiabatic heating of the mixture.

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