expansion wave

expansion wave

[ik′span·shən ‚wāv]
(fluid mechanics)
A pressure wave or shock wave that decreases the density of air as the air passes through it.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

expansion wave

expansion waveclick for a larger image
In supersonic flow, expansion waves occur when bodies begin to narrow, making more space available. In passing through an expansion wave, air velocity increases, while temperature and pressures are reduced. A simple wave or progressive disturbance in the isentropic flow of a compressible fluid, such that the pressure and density of a fluid particle decrease on crossing the wave in the direction of its motion. It is the opposite of a compression wave. Also called a rarefaction wave. See also compression wave.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
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This leads to the formation of an expansion wave, causing the gas jet to expand in the radial direction and increase the potential jet core.
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Figure 11 shows the predicted results for a = 7.5[degrees], where T is time period and time reference (t = 0) is the time for radiation of an expansion wave near the trailing edge.
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The 14-X B model lower surface was designed based on the two-dimensional compressible flow (oblique shock wave relationships) and expansion wave (Prandtl-Meyer theory), considering the simplest case, that is, no viscous flow, calorically perfect air ([gamma] = 1.4), and scramjet engine with power off [11].
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The reason why the amplitude remains a decreasing tendency in R2 area is that there is expansion wave in the junction region (in Figure 6(a), x = 1;in Figure 6(c), x = 0) between the spherical nose and the straight cone which is caused by the surface curve discontinuity [25].
Temporal and spatial evolution characteristics of disturbance wave in a hypersonic boundary layer due to single-frequency entropy disturbance
The shock wave becomes a Prandtl-Meyer expansion wave (i.e., [M.sub.2] > [M.sub.1]) for very high values of [Re.sub.2]/[Re.sub.1].
On the effects of viscosity on the shock waves for a hydrodynamical case--part I: basic mechanism
In analyzing the expansion wave at the nozzle outlet, the analysis must begin in the nozzle, move to the nozzle outlet, and then after the nozzle.
Analysis of expansion waves appearing in the outlets of two-phase flow nozzles
In the laser spallation test, strong pulse expansion wave was produced by the pulse laser ablation of the confined silicone grease on the opposite surface of the diamond film and was utilized to cause Mode-I delamination of diamond film.
AE monitoring from CVD-diamond film subjected to micro-indentation and pulse laser spallation
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