Showing papers on "Rarefaction published in 1979"
30 Oct 1979
TL;DR: In this paper, eight applications of the Random-Choice Method (RCM) to the solution of problems in shock and detonation-wave dynamics are presented, and it is shown that unlike other numerical methods, the RCM yields sharp-fronted shocks and contact surfaces without resorting to artificial and perhaps erroneous means of predicting their locations.
Abstract: : Eight applications of the Random-Choice Method (RCM) to the solution of problems in shock and detonation-wave dynamics are presented. It is shown that unlike other numerical methods, the RCM yields sharp-fronted shocks and contact surfaces without resorting to artificial and perhaps erroneous means of predicting their locations. It has been shown by examples that the RCM provides exceptionally high computational accuracy for flows involving planar and spherical shock waves, rarefaction waves and contact surfaces, as well as their interactions. In addition, the RCM can handle flows with detonations and chemical reactions involving the above transition fronts.
14 citations
Journal Article•
TL;DR: The functional rarefaction of small arterioles previously reported at 6 weeks of age in the SHR has been shown to be a structural decrease in arteriolar density as well, and the high "occlusive tone" normally found in young normotensive rats is observed in the older SHR.
Abstract: The functional rarefaction of small arterioles previously reported at 6 weeks of age in the SHR has been shown to be a structural decrease in arteriolar density as well. In addition, the high "occlusive tone" normally found in young normotensive rats is observed in the older SHR. This elevated tone contributes to a functional rarefaction in the older SHR arterioles. The mechanism for the rarefaction appears to be related to the cAMP/cGMP second messenger system.
9 citations
01 Jan 1979
TL;DR: In this article, a model for dislocation generation in shock-wave deformation is described, which does not require the dislocations to move with the shock front; therefore no supersonic disllocations are needed.
Abstract: A model for dislocation generation in shock-wave deformation is described. Contrary to earlier models proposed by Smith (1958) and Hornbogen (1960), this model does not require the dislocations to move with the shock front; therefore no supersonic dislocations are needed. Dislocations are homogeneously nucleated at the shock front by the deviatoric component of the applied stress pulse; after generation, they are left behind, organizing themselves into more stable arrangements. Dislocation generation may also take place at the rarefaction part of the wave; however the mechanism is thought to be the conventional multiplication mechanism in this part of the wave. Dynamical considerations for nickel show that dislocations moving at velocities higher than the transverse sound velocity would lead to exceedingly high temperatures; experiments show that such is not the case. What renders the proposed model especially attractive is that, for the first time, quantitative predictions of residual dislocation densities are made possible. Accordingly, calculated dislocation densities are compared to observed densities for nickel reported in the literature.
5 citations
TL;DR: In this paper, the theory of double discontinuities is used to analyze possible quasisteady flows which appear in the ambient atmosphere under the action of laser radiation, and the limits of existence of various regimes are determined and it is shown that transitions between them may be characterized by hysteresis.
Abstract: The theory of double discontinuities is used to analyze possible quasisteady (with a rarefaction wave) flows which appear in the ambient atmosphere under the action of laser radiation. The limits of existence of various regimes are determined and it is shown that transitions between them may be characterized by hysteresis. The calculated dependences are confirmed experimentally.
4 citations
01 Feb 1979
TL;DR: In this paper, the Particle-in-Cell method for the numerical solution of problems in fluid dynamics was extended to the study of shock and rarefaction flows in a multiphase mixture.
Abstract: The Particle-in-Cell method for the numerical solution of problems in fluid dynamics was extended to the study of shock and rarefaction flows in a multiphase mixture. To test the numerical procedure, the propagation of sound signals through a mixture in which the theoretical speed is appreciably less than that of either material separately was examined, with results that validate the calculational technique. The stability of an interface between a gas and a fragmented metal impacted by shock or rarefaction was also studied. The resulting calculations give an accurate differentiation between the stable case, for which the interface should stay sharp, and the unstable case, for which there should be interpenetration. Information on both the details of interpenetration and its effects on the overall dynamics is presented. 17 figures, 12 tables.
3 citations
TL;DR: In this paper, an exact solution of MHD channel flow of a rarefied gas has been carried out on taking into account the external circuit, where closed form solutions have been derived for velocity, amplitude, current density, magnetic field, normalised flow rate and the skin-friction.
2 citations
TL;DR: In this paper, the authors investigated five simple models, three analytic and two numerical models, to examine the relationship between the entry time of the rarefaction and the time of its overtaking the initiating shock wave in a solid explosive.
2 citations
2 citations
01 Jan 1979
TL;DR: In this paper, a study of the time dependent interaction of an initially uniform equilibrium plasma with a plane conducting surface was made in order to achieve a more complete understanding of the dynamics of the charging process and of the approach to the floating potential on the surface.
Abstract: A study of the time dependent interaction of an initially uniform equilibrium plasma with a plane conducting surface was made in order to achieve a more complete understanding of the dynamics of the charging process and of the approach to the floating potential on the surface. Numerical solutions of the cold ion equations of motion in conjunction with equilibrium electrons and Poisson's equation show the formation of an ion-rich sheath near the surface and the coupling of the non-neutral region to the undisturbed plasma through a quasineutral rarefaction. Analytical treatment of the quasineutral region showed excellent agreement (within 1 percent) with the numerical results.
2 citations
1 citations
Journal Article•
TL;DR: In this article, the limit of small rarefaction for linearized plane Couette flow of a rarefied gas with molecular interactions of infinite range is considered and the mean velocity and other relevant moments of the distribution function are given up to the order corresponding to the first order inner and outer approximations to the distribution functions.
01 Jan 1979
TL;DR: In this paper, a method for calculation of laminar and rarefied aerodynamic heating to the external tank of the Space Shuttle during the ascent phase of flight is presented.
Abstract: A practical method has been developed for calculation of laminar and rarefied aerodynamic heating to the external tank of the Space Shuttle during the ascent phase of flight. A modification of laminar boundary theory is used as the basis for the heating relation. This relation is used in conjunction with a correlation for surface pressures to obtain undisturbed aerodynamic heating. Interference effects on the external tank due to the orbiter are correlated using the rarefaction parameter which was developed as part of the heating relation. The effects of rarefaction on the undisturbed and interference heating are illustrated with test data.