Gas jets as ultrasonic waveguides
UNSPECIFIED. (2003) Gas jets as ultrasonic waveguides. JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, 114 (3). pp. 1254-1265. ISSN 0001-4966Full text not available from this repository.
Official URL: http://dx.doi.org/10.1121/1.1596169
The study of the propagation of ultrasound within a gas jet is extended to obtain waveguide effects, where the jet collimates the ultrasonic beam from a transducer within the flow. Two methods have been investigated to achieve this-cooling the gas within the air jet, and using a different gas whose acoustic velocity is lower than air. Cooling an air jet to a temperature less than that of the surrounding air produced a noticeable waveguide effect. In addition, studies have been carried out using other selected gases, such as carbon dioxide (CO2) with a lower acoustic velocity than air, and helium (He) with a higher value. The former gas enhanced confinement of the ultrasonic beam, whereas the latter caused divergence. An ideal solution was found to be a CO2 /air mixture, which produced a well-collimated sound field along the axis, while limiting the excess attenuation of pure CO2 gas jets. The effectiveness of the waveguide using mixed gas jets in producing images in air-coupled testing of solids is demonstrated. (C) 2003 Acoustical Society of America.
|Item Type:||Journal Article|
|Subjects:||T Technology > TA Engineering (General). Civil engineering (General)|
|Journal or Publication Title:||JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA|
|Publisher:||ACOUSTICAL SOC AMER AMER INST PHYSICS|
|Official Date:||September 2003|
|Number of Pages:||12|
|Page Range:||pp. 1254-1265|
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