Theoretical and Experimental Results for Coaxial‐Flow Jet Noise

The noise from cold subsonic coaxial jets issuing from concentric nozzles with external mixing has been examined and an attempt made to relate the results to the flow patterns of the jets. As the velocity of the annular jet was increased in relation to a given central jet velocity, an initial attenuation of the jet noise was observed. On further increasing the annular jet velocity until the velocities of the two streams were nearly equal, the noise was in excess of that of the central jet alone. An attempt has been made to predict the curve relating the attenuation attained to the coaxial jet velocity. In comparing the attenuation produced by a coaxial jet combination with that of a single jet, it could be argued that the total thrust in each case should be the same and experimental results are presented on this basis. Results are also available for a nozzle configuration in which the jets are mixed internally in a tube before discharge, and the paper is completed with the results obtained from an annular nozzle acting alone.

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Comparison of holography, beamforming, and intensity-based inverse measurements on full-scale jet noise sources. Part II: Experimental results

The Journal of the Acoustical Society of America ◽

10.1121/1.4934030 ◽

2015 ◽

Vol 138 (3) ◽

pp. 1917-1917

Author(s):

Blaine M. Harker ◽

Alan T. Wall ◽

Trevor A. Stout ◽

Tracianne B. Neilsen ◽

Kent L. Gee ◽

...

Keyword(s):

Jet Noise ◽

Full Scale ◽

Experimental Results ◽

Noise Sources

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Jet noise simulation on shallow water

Journal of Fluid Mechanics ◽

10.1017/s0022112070000241 ◽

1970 ◽

Vol 40 (2) ◽

pp. 423-432 ◽

Cited By ~ 3

Author(s):

R. B. Webster

Keyword(s):

Shallow Water ◽

Jet Noise ◽

Experimental Results ◽

Aerodynamic Noise ◽

Wall Roughness ◽

Free Jet ◽

Noise Simulation ◽

Water Simulation ◽

Variable Wall ◽

Good Agreement

A quantitative shallow water simulation technique for aerodynamic noise study is investigated. The technique is employed for the case of a free jet issuing from a nozzle with variable wall roughness.The experimental results obtained are in remarkably good agreement with the theory. It is concluded that there is great potential for further work in even less well understood areas of aerodynamic noise research.

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Diagnostics of Gold Laser Plasmas

International Astronomical Union Colloquium ◽

10.1017/s0252921100108085 ◽

1988 ◽

Vol 102 ◽

pp. 357-360

Author(s):

J.C. Gauthier ◽

J.P. Geindre ◽

P. Monier ◽

C. Chenais-Popovics ◽

N. Tragin ◽

...

Keyword(s):

Experimental Results ◽

Pure Gold ◽

Electronic Temperature ◽

X Ray ◽

Laser Plasmas ◽

Collisional Radiative Model ◽

Radiative Model

AbstractIn order to achieve a nickel-like X ray laser scheme we need a tool to determine the parameters which characterise the high-Z plasma. The aim of this work is to study gold laser plasmas and to compare experimental results to a collisional-radiative model which describes nickel-like ions. The electronic temperature and density are measured by the emission of an aluminium tracer. They are compared to the predictions of the nickel-like model for pure gold. The results show that the density and temperature can be estimated in a pure gold plasma.

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Observation of Phase Contrast Images in STEM and CTEM Modes by Using 100 kV Field Emission Electron Gun

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051967 ◽

1974 ◽

Vol 32 ◽

pp. 390-391

Author(s):

Y. Harada ◽

T. Goto ◽

H. Koike ◽

T. Someya

Keyword(s):

Field Emission ◽

Phase Contrast ◽

Image Formation ◽

Fresnel Diffraction ◽

Experimental Results ◽

Electron Gun ◽

Scanning Microscopy ◽

Emission Electron ◽

Lattice Images

Since phase contrasts of STEM images, that is, Fresnel diffraction fringes or lattice images, manifest themselves in field emission scanning microscopy, the mechanism for image formation in the STEM mode has been investigated and compared with that in CTEM mode, resulting in the theory of reciprocity. It reveals that contrast in STEM images exhibits the same properties as contrast in CTEM images. However, it appears that the validity of the reciprocity theory, especially on the details of phase contrast, has not yet been fully proven by the experiments. In this work, we shall investigate the phase contrast images obtained in both the STEM and CTEM modes of a field emission microscope (100kV), and evaluate the validity of the reciprocity theory by comparing the experimental results.

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A new dissociation mode for dislocations in silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100108878 ◽

1978 ◽

Vol 36 (1) ◽

pp. 346-347

Author(s):

A. Ourmazd ◽

G.R. Booker ◽

C.J. Humphreys

Keyword(s):

Detailed Examination ◽

Experimental Results ◽

Dislocation Network ◽

Weak Beam ◽

Phosphorus Doped

A (111) phosphorus-doped Si specimen, thinned to give a TEM foil of thickness ∼ 150nm, contained a dislocation network lying on the (111) plane. The dislocation lines were along the three <211> directions and their total Burgers vectors,ḇt, were of the type , each dislocation being of edge character. TEM examination under proper weak-beam conditions seemed initially to show the standard contrast behaviour for such dislocations, indicating some dislocation segments were undissociated (contrast A), while other segments were dissociated to give two Shockley partials separated by approximately 6nm (contrast B) . A more detailed examination, however, revealed that some segments exhibited a third and anomalous contrast behaviour (contrast C), interpreted here as being due to a new dissociation not previously reported. Experimental results obtained for a dislocation along [211] with for the six <220> type reflections using (g,5g) weak-beam conditions are summarised in the table below, together with the relevant values.

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