Showing papers on "Rarefaction published in 1980"
TL;DR: In this article, it was shown that a vacuum state must be bounded by rarefaction waves and that compression vacuums can give rise to compression waves which eventually form shock.
167 citations
TL;DR: Brain stem auditory responses were evoked by stimulation with condensation (C) and rarefaction (R) clicks separately and latencies of the first five waves of the response were compared in response to the two sound pressure directions.
Abstract: Brain stem auditory responses were evoked by stimulation with condensation (C) and rarefaction (R) clicks separately. The latencies of the first five waves of the response were compared in response to the two sound pressure directions. Responses to R clicks were significantly shorter than responses to C clicks for wave 4, in the absence of consistent response differences in the other waves.
38 citations
12 citations
TL;DR: In this article, profile modification of laser plasmas, in the transition layer at critical density and in the flow on the overdense side, is studied assuming isothermal flow and low absorption within the layer, compression transitions are proved impossible and cavities possible only in subsonic flow.
Abstract: Profile modification of laser plasmas, in the transition layer at critical density and in the flow on the overdense side, is studied Assuming isothermal flow and low absorption within the layer, compression transitions are proved impossible and cavities possible only in subsonic flow The overdense flow adjusts itself for a rarefaction transition in a manner (formation of plateaus, bumps, or cavities) critically dependent on how the (spatially uniform) temperature varies with time Spherical effects and evidence for the results are considered
11 citations
TL;DR: Five psychophysical functions for visual density are obtained with the use of the magnitude-estimation method and it is found that apparent rarefaction is barely detectable for sides longer than 10–15 cm (6–9 deg).
Abstract: Five psychophysical functions for visual density are obtained with the use of the magnitude-estimation method. Because of apparent rarefaction, a different psychophysical function ensues for each size of square used. It is found that apparent rarefaction is barely detectable for sides longer than 10–15 cm (6–9 deg). It is also found that apparent rarefaction occurs to the greatest extent when short interlinear spacings are used.
7 citations
TL;DR: In this article, a novel experimental set-up for obtaining shock-wave superposition is described, where two opposite sides of an explosive layer placed directly in contact with a steel block are simultaneously initiated at the two opposite side of the explosive layer.
Abstract: A novel experimental set-up for obtaining shock-wave superposition is described. Detonation is simultaneously initiated at the two opposite sides of an explosive layer placed directly in contact with a steel block. It was possible to take advantage of thea (bcc) → e (hcp) →α (bcc) transformation occurring in iron at approximately 13 GPa in a unique fashion. The pressure of the two converging pulses is approximately 13 GPa, resulting in little or no transformation. However, in the region of superposition of the two waves the pressure is much higher.Post explosionem observation of the microstructure allowed an easy identification of the region of superposition, because of the profuse transformation “debris”. Events conducted for three thicknesses of the explosive layers allowed conclusions to be drawn about the changes of rarefaction and attenuation rates. The interactions occurring between the waves due to simultaneous superposition and transformation are thought to be responsible for internal spalling.
5 citations
4 citations
TL;DR: In this paper, the authors developed a computer program that combines the capabilities of PTA-1 and PTAC to analyze pressure transients in the intermediate heat transport system of a sodium-cooled breeder reactor.
Abstract: Computational methods for analyzing pressure transients in the intermediate heat transport system of a sodium-cooled breeder reactor are being developed at Argonne National Laboratory. Because these systems typically operate at low pressures, thin-walled piping is used. Consequently, the pressure pulses produced by a sodium/water reaction in a steam generator or a pipe break may plastically deform sections of the piping, and rarefaction waves, because of the low operating pressure, may produce cavitation in the system. Both these phenomena have a large effect on the pressure pulses traversing the pipe network and, consequently, on the transient loading on major components. The computer program PTA-1, which includes the effect of plastic deformation of piping, and the computer program PTAC, which includes the effect of cavitation, have previously been validated using available experimental data. A new program, PTA-2, is being developed which combines the capabilities of PTA-1 and PTAC. Comparisons will be shown between PTA-2 predictions and the results of several experiments performed at Stanford Research Institute. In each of these experiments, a pressure pulse caused plastic deformation of a thin-walled pipe, producing a rarefaction wave which then produced a cavitated region in another pipe.
4 citations
TL;DR: In this article, an explicit solution for arbitrary γ is given and applied specifically to the case γ = 4/3, corresponding to a polyatomic ideal gas, and explicit solutions are obtained for γ=5/3 and γ ≥ 7/5, respectively, for monoatomic and diatomic ideal gases.
Abstract: A one‐dimensional gas flow is generated by a piston which moves at a constant velocity out of a pipe filled with gas. The piston causes a rarefaction wave which is reflected against the closed end of the pipe. According to the theory as described by Landau and Lifshitz the reflection process is governed by the solution of a linear partial differential equation with the adiabatic exponent γ as a parameter. Explicit solutions are obtained for γ=5/3 and γ=7/5, corresponding to the theoretical values for monoatomic and diatomic ideal gases, respectively. In this paper an explicit solution for arbitrary γ is given and applied specifically to the case γ=4/3, corresponding to a polyatomic ideal gas.
3 citations
TL;DR: Flow of a liquid through distensible tubes is of interest primarily in biological systems, and some properties of shock waves in such tubes are discussed.
Abstract: Flow of a liquid through distensible tubes is of interest primarily in biological systems, and some properties of shock waves in such tubes are discussed. In shock-fixed coordinates, these flows are steady, and the shock is associated with an increase of pressure and cross-sectional area. Shock transition is analyzed for two flow models, namely, immediate flow separation, when the flow enters the shock zone, and no separation. Shock properties are expressed in terms of the speed index (ratio of the velocity of the shock to that of a small-amplitude wave) and dissipation (loss of total pressure). Examples are worked out for the thoracic aorta of an anesthetized dog, a perfectly elastic tube, and a partially collapsed tube. Appreciable differences in shock velocity and dissipation result if either flow separation or no separation is assumed.
3 citations
05 Aug 1980
TL;DR: In addition to a second-sound-compression shock wave, a rarefaction shock wave can be observed at distances of the order of several centimeters from the radiator when a short, high-power, thermal pulse propagates in superfluid helium as discussed by the authors.
Abstract: In addition to a second-sound-compression shock wave, a rarefaction shock wave can be observed at distances of the order of several centimeters from the radiator when a short, high-power, thermal pulse propagates in superfluid helium.
TL;DR: In this paper, the equations which describe the resonant interaction of short and long waves are exactly solved by Hirota's method. But the N -soliton solution which corresponds to the dark soliton as the short wave and rarefactive soliton (RSS) as the long wave are given.
Abstract: The equations which describe the resonant interaction of short and long waves are exactly solved by Hirota's method. The N -soliton solution which corresponds to the dark soliton as the short wave and rarefactive soliton as the long wave are given.
TL;DR: An exact analysis of the heat transfer in MHD fully-developed channel flow of rarefied gas has been presented on taking into account the external circuit in this article, where closed from solutions have been derived for temperature and Nusselt number.
TL;DR: In this paper, the authors considered the propagation of a pressure wave through an imploding liquid metal liner near turnaround, due to the compression of magnetic flux and plasma, based on which the pressure distribution near turnaround was derived analytically under the assumption of a small Mach number M (defined by the ratio between characteristic radial velocity of liner and the velocity of sound through the medium).
Abstract: The propagation of a pressure wave through an imploding liquid metal liner near turnaround, due to the compression of magnetic flux and plasma is considered, based on which the pressure distribution near turnaround is derived analytically under the assumption of a small Mach number M (defined by the ratio between characteristic radial velocity of liner and the velocity of sound through the medium). It is shown that under certain conditions, the rarefaction wave from the outer (free) surface causes the apparition of a negative pressure in the imploding liner, with consequent liability of cavitation. The criterion for the generation of the negative pressure is found to be MΛ0.6~0.7 for the range of parameters considered (A: liner thickness at turnaround normalized by the inner radius).