scholarly journals On the Formation of Interstellar Gas Clouds

1958 ◽  
Vol 8 ◽  
pp. 943-943
Author(s):  
S. A. Kaplan
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Wave Theory ◽  
Density Fluctuations ◽  
Interstellar Space ◽  
Interstellar Gas ◽  
Degree Of Ionization ◽  
Great Density ◽  
Characteristic Features ◽  
Shock Wave Theory

The characteristic features of interstellar gas clouds—existence of large density fluctuations, their connection with cosmic dust, stretching along the magnetic fields, and so on—may be described by a shock wave theory in interstellar space.The author has developed a theory of stationary shock waves accompanied by losses of energy by means of radiation. Choosing two surfaces on both sides of the front, so that the regions of energy radiation should lie between them, we can write an equation for the mass flow and for the impulse conservation between these surfaces, and two equations which determine the stationary temperature of the gas in the field of interstellar radiation. The solution of this system of equations permits one to determine the general changes of thermodynamic and other parameters for the transition of gas through the shock wave with regions of radiative cooling. If changes of the degree of ionization take place, and a magnetic field is present, some terms should necessarily be added to the corresponding equations.The boundary between the interstellar gas cloud and the intercloud medium must represent the shock wave accompanied by losses of energy by means of radiation, because such ruptures may probably be supposed as the sole explanation of stability of the great density changes (a hundred times and more) often observed in the interstellar space.In this paper we give some results of the theory of shock waves accompanied by radiative losses of energy.

Global-Space Propagating Characteristics of Pulsed-Laser-Induced Shock Waves

2003 ◽  
Vol 17 (19) ◽  
pp. 1057-1066 ◽  
Author(s):  
Zhihua Li ◽  
Duanming Zhang ◽  
Boming Yu ◽  
Li Guan
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Pulsed Laser ◽  
Wave Theory ◽  
Point Explosion ◽  
Theoretical Predictions ◽  
Shock Wave Theory ◽  
Plasma Shock Wave ◽  
Relationship Of ◽  
Plasma Shock

Under the propagating limitation-conditions and based on the pulsed-laser-induced plasma shock wave theory,1 the propagating rules in the global free space (including close areas and mid-far areas) of pulsed-laser-induced shock waves are established for the first time. Compared with the previous work by Bian et al.,2 our theoretical model can directly lead to the relationship of the initial Mach number M0 of plasma shock waves and the whole energy E released into plasma shock waves from a pulsed laser without any approximations or any unnecessary experimental parameters. Here, M0 is also related to the pulse duration τ0 and the sound velocity υ0 in the atmosphere; the variation of attenuation index τ, as a function of laser parameters (especial τ0), is also obtained, and our theoretical predictions of mid-far propagating rules of plasma shock waves are in good agreement with experimental results. In addition, it should be noted that Sedov–Taylor solutions to the ideal shock wave in a point explosion are only the approximations of the propagating rules in the mid-far area of pulsed-laser plasma shock waves that we obtained.

Delta Wings of Shapes Amenable to Exact Shock-wave Theory

1963 ◽  
Vol 67 (625) ◽  
pp. 39-40 ◽  
Author(s):  
T. Nonweiler
Keyword(s):  
Shock Wave ◽  
Mach Number ◽  
Shock Waves ◽  
Hypersonic Flow ◽  
Cross Section ◽  
Wave Theory ◽  
Wave System ◽  
Delta Wings ◽  
Shock Wave Theory

SummaryA class of delta wings is considered, whose under-surface has an inverted-V, or inverted-W, cross section of such a form that, at the “design” Mach number and incidence, the shock waves formed are plane. The geometry of the shock-wave system and surface is described briefly, and comments made about the utility of the concept in relation to hypersonic flow studies.

Destruction Analysis of Broadside Multi-Cabin Protective Structure of Warship under Explosion Loading

2013 ◽  
Vol 395-396 ◽  
pp. 866-870
Author(s):  
Long Guang Jiang ◽  
Xiao Dong Zhang
Keyword(s):  
Shock Wave ◽  
Wave Attenuation ◽  
Wave Theory ◽  
Protective Structure ◽  
Naval Vessel ◽  
Reflected Shock ◽  
Defensive Structure ◽  
Explosion Loading ◽  
Shock Wave Theory ◽  
Extent Of Damage

Shock wave parameters of cabins for shipboard defensive structure are studied based on shock wave theory. The destroy of defensive structure can be estimated by impulse of shock wave. In the process of air shock wave propagating, isentropic suction wave is reflected from void cabin into defense structure. The solution of shock wave attenuation of void cabin can be reached by using isentropic line to replace the shock adiabatic of the reflected shock. It can be seen from the example that the multi-layers defense structure system of warship is very important to decrease the damage from explosive shock wave. The method can be used to predict the extent of damage of naval vessel.

An application of shock wave theory to traffic signal control

1981 ◽  
Vol 15 (1) ◽  
pp. 35-51 ◽  
Author(s):  
Panos G. Michalopoulos ◽  
Gregory Stephanopoulos ◽  
George Stephanopoulos
Keyword(s):  
Shock Wave ◽  
Wave Theory ◽  
Traffic Signal ◽  
Signal Control ◽  
Traffic Signal Control ◽  
Shock Wave Theory

scholarly journals Herbig-Haro Objects

1977 ◽  
Vol 42 ◽  
pp. 1-24
Author(s):  
K.H. Böhm
Keyword(s):  
Shock Wave ◽  
Geometrical Structure ◽  
Wave Theory ◽  
Theoretical Models ◽  
Emission Lines ◽  
Low Density ◽  
Line Formation ◽  
Line Profiles ◽  
Apparent Paradox ◽  
Shock Wave Theory

The available observational information on the geometrical structure, emission line and continuous spectra, line profiles, radial velocities and linear polarization of Herbig-Haro objects is briefly reviewed. We emphasize the inhomogeneous structure of the “classical” Herbig-Haro objects and the appearance of small “condensations” with radii of ~300-900 a.u. The apparent paradox of the presence of “gaseous nebula type” as well as “reflection type” Herbig-Haro objects is discussed.A purelyempiricalmodel of the regions of line formation is discussed. It shows that regions of low density (Ne~103cm-3) cover the space between the condensations and most of the volume of the condensations themselves. Only between 0.1 and 1% of the volume of the condensations is covered by a high density medium (Ne~ 4 x 104cm-3, N ~105cm-3) which, however, contributes very strongly to the formation of the spectrum.Differenttheoretical modelsfor the line forming regions are discussed. We strongly favor the shock wave theory in which the emission lines are formed in the cooling regions of (running) shock waves. The general agreement between observations and the new calculations by Raymond is emphasized, and the few remaining discrepancies are discussed. The possibilities of explaining other properties of Herbig-Haro objects (including time scales, sizes and filling factors of condensations) are described.

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