arXiv subjects

R. K. Anand

Publications and source records attributed to R. K. Anand.

8 recordsLinked to original sources

arXiv2025

On the Convergence of Strong Cylindrical and Spherical Shock Waves in Solid Materials

In this article, we present a description of the behaviour of shock-compressed solid materials following the Geometrical Shock Dynamics (GSD) theory. GSD has been successfully applied to various gas dynamics problems, and here we have employed it to investigate the propagation of cylindrically and spherically symmetric converging shock waves in solid materials. The analytical solution of shock dynamics equations has been obtained in strong-shock limit, assuming the solid material to be homogeneous and isotropic and obeying the Mie-Gruneisen equation of state. The non-dimensional expressions are obtained for the velocity of shock, the pressure, the mass density, the particle velocity, the temperature, the speed of sound, the adiabatic bulk modulus, and the change-in-entropy behind the strong converging shock front. The influences as a result of changes in (i) the propagation distance r from the axis or centre (r=0) of convergence, (ii) the Gruneisen parameter, and (iii) the material parameter are explored on the shock velocity and the domain behind the converging shock front. The results show that as the shock focuses at the axis or origin, the shock velocity, the pressure, the temperature, and the change-in-entropy increase in the shock-compressed titanium Ti6Al4V, stainless steel 304, aluminum 6061-T6, etc.

cond-mat.mtrl-sci↗

arXiv2018

On the strong spherical shock waves in a two-phase gas-particle medium

In this paper, power series solutions for strong spherical shocks of time dependent variable energy propagating in a two-phase gas-particle medium are presented taking into consideration the power series solution technique (Sakurai in J Phys Soc Jpn 8:662-669,1953; Freeman in J Phys D Appl Phys 2(1):1697-1710,1968). Assuming the medium to be a mixture of a perfect gas and small solid particles, the power series solutions are obtained in terms of M^-2, where M is the upstream Mach number of shock. This investigation presents an overview of the effects due to an increase in (i) the propagation distance from the inner expanding surface and, (ii) the dust loading parameters on flow-field variables such as the velocity of fluid, the pressure, the density, and also on the speed of sound, the adiabatic compressibility of mixture and the change-in-entropy behind the strong spherical shock front.

astro-ph.HE↗

arXiv2014

On dynamics of imploding shock waves in a mixture of gas and dust particles

In this paper, the generalized analytical solutions for one-dimensional adiabatic flow behind the imploding shock waves propagating in a dusty gas are obtained using the geometrical shock dynamics theory. The dusty gas is assumed to be a mixture of a perfect gas and spherically small solid particles, in which solid particles are continuously distributed. Shock jump relations given by Anand for a dusty gas are taken into consideration to explore the effects due to an increase in (i) the propagation distance from the centre of convergence, (ii) the mass fraction of solid particles in the mixture and (iii) the ratio of the density of solid particles to the initial density of the gas, on the shock velocity, pressure, temperature, density, velocity of mixture, speed of sound, adiabatic compressibility of mixture and the change-in-entropy across the shock front. The results provided a clear picture of whether and how the presence of solid particles influences the flow field behind the imploding shock front.

astro-ph.HE↗

arXiv2013

On the structure of MHD shock waves in a viscous gas

The exact solutions for MHD shock waves in an ideal gas are obtained taking into consideration only the viscosity of the gas. In view of an axial magnetic field, the analytical expressions for the particle velocity, temperature, pressure and change-in-entropy within the shock transition region are obtained. The flow variables are numerical analysed to explore the influence of static magnetic field, shock strength, specific heat ratio, initial pressure, initial density and coefficient of viscosity on the flow variables. The findings confirm that thickness of MHD shock front increases with increase in the viscosity of the gas and the change in thickness is more noticeable for large values of the strength of magnetic field. The results provided a clear picture of whether and how the viscosity of gas and the magnetic field affect the thickness of shock front.

astro-ph.HE↗

arXiv2013

Shock dynamics of strong imploding cylindrical and spherical shock waves with non-ideal gas effects

In this paper, the generalized analytical solution for one dimensional adiabatic flow behind the strong imploding shock waves propagating in a non-ideal gas is obtained by using the geometrical shock dynamics theory. The equation of state for non-ideal gas as given by Landau and Lifshitz and the generalized shock jump relations derived by Anand are taken into consideration to explore the effects due to an increase in (i) the propagation distance from the centre of convergence, (ii) the non-idealness parameter and, (iii) the adiabatic index, on the shock velocity, pressure, density, particle velocity, sound speed, adiabatic compressibility and the change in entropy across the shock front. The findings provided a clear picture of whether and how the non-idealness parameter and the adiabatic index affect the flow field behind the strong imploding shock front.

astro-ph.HE↗

arXiv2013

Shock jump relations for a dusty gas atmosphere

This paper presents generalized forms of jump relations for one dimensional shock waves propagating in a dusty gas. The dusty gas is assumed to be a mixture of a perfect gas and spherically small solid particles, in which solid particle are continuously distributed. The generalized jump relations reduce to the Rankine-Hugoniot conditions for shocks in an idea gas when the mass fraction (concentration) of solid particles in the mixture becomes zero. The jump relations for pressure, density, temperature, particle velocity, and change-in-entropy across the shock front are derived in terms of upstream Mach number. Finally, the useful forms of the shock jump relations for weak and strong shocks, respectively, are obtained in terms of the initial volume fraction of the solid particles. The computations have been performed for various values of mass concentration of the solid particles and for the ratio of density of solid particles to the constant initial density of gas. Tables and graphs of numerical results are presented and discussed.

astro-ph.EP↗

arXiv2012

Jump relations for magnetohydrodynamic shock waves in non-ideal gas flow

The generalized jump relations across the magnetohydrodynamic (MHD) shock front in non-ideal gas are derived considering the equation of state for non-ideal gas as given by Landau and Lifshitz. The jump relations for pressure, density, and particle velocity have been derived, respectively in terms of a compression ratio. Further, the simplified forms of the MHD shock jump relations have been obtained in terms of non-idealness parameter, simultaneously for the two cases viz., (i) when the shock is weak and, (ii) when it is strong. Finally, the cases of strong and weak shocks are explored under two distinct conditions viz., (i) when the applied magnetic field is strong and, (ii) when the field is weak. The aim of this paper is to contribute to the understanding of how shock waves behave in magnetized environment of non-ideal gases.

astro-ph.HE↗

arXiv2012

Jump relations across a shock in non-ideal gas flow

Generalized forms of jump relations are obtained for one dimensional shock waves propagating in a non-ideal gas which reduce to Rankine-Hugoniot conditions for shocks in idea gas when non-idealness parameter becomes zero. The equation of state for non-ideal gas is considered as given by Landau and Lifshitz. The jump relations for pressure, density, temperature, particle velocity, and change in entropy across the shock are derived in terms of upstream Mach number. Finally, the useful forms of the shock jump relations for weak and strong shocks, respectively, are obtained in terms of the non-idealness parameter. It is observed that the shock waves may arise in flow of real fluids where upstream Mach number is less than unity.

astro-ph.HE↗