Enclosure-Induced Interference Effects in a Miniaturized Sidescan Sonar
2012 (English)In: IEEE Journal of Oceanic Engineering, ISSN 0364-9059, E-ISSN 1558-1691, Vol. 37, no 2, 236-243 p.Article in journal (Refereed) Published
On, for instance, the miniaturized submersible explorer, Deeper Access, Deeper Understanding (DADU), only 20 cm in length and 5 cm in diameter, the sidescan sonar needs to be tightly mounted in the hull. Finite element analysis (FEA) as well as physical measurements were used to investigate the effects of beam interaction with acoustically nearby rigid boundaries. Computer simulations showed the first major dip in the beam shape to vary in strength, size, and position with the enclosure wall height, from a position of 47° at 0.0-mm wall height to 32° at 3.0-mm wall height. Hydrophonic measurements on the manufactured test device confirmed these values to within 9%, varying between 47° and 29°. In addition, Schlieren imaging was proposed and used as a noninvasive means of qualitative beam shape characterization. A field test was performed with the enclosure height set to 0 and 3 mm. With the latter height, a dark band, corresponding to a sonar sensitivity dip at about 30° in the beam, appeared in the sonar image. It was found that the beam shape is sensitive to small mounting errors, in this case where the wavelength of the sonar is on the same size scale as the enclosure. Furthermore, it was found that FEA models can be used to accurately predict enclosure effects on sonar beam shapes, and Schlieren imaging can be used to visually detect the shape deformations in mounted sonar devices.
Place, publisher, year, edition, pages
2012. Vol. 37, no 2, 236-243 p.
Beam shape, finite element analysis (FEA), miniaturize, Schlieren, sidescan sonar
Fluid Mechanics and Acoustics
Research subject Engineering Science with specialization in Microsystems Technology
IdentifiersURN: urn:nbn:se:uu:diva-171730DOI: 10.1109/JOE.2012.2188160ISI: 000303326500007OAI: oai:DiVA.org:uu-171730DiVA: diva2:512215
ProjectsDeeper Access, Deeper Understanding (DADU)