Proceedings of the Korean Society for Noise and Vibration Engineering Conference (한국소음진동공학회:학술대회논문집)
- 2004.11a
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- Pages.482-485
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- 2004
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- 1598-2548(pISSN)
Actively controlled sound field of upper sections attached to noise harriers
방음벽 상단 소음의 회절에 관한 능동제어
-
Koh, Hyo-In
;
- Moser, Michael (Institute of Technical Acoustics, Technical University Berlin)
-
고효인
(한국철도기술연구원)
;
- Michael Möser (Institute of Technical Acoustics, Technical University Berlin)
- Published : 2004.11.01
Abstract
On the basis of theoretical studies on the effect of the cylinders attached to semi-infinite screens, the tangential sound power-transport parallel to the surface of the attached cylinder is minimized by means of a secondary sound field, which is generated from a part of the attached cylinder. The numerical study shows the possibility of deflecting the incident sound by minimizing the acoustic surface impedance of the upper sections. The acoustical shadow region was more pronounced in both near- and far-field compared to the passive case with rigid surface, i.e. without active control. For a relatively wide frequency range it was possible to enhance shielding effects only with few secondary sources and error microphones. In this paper effects of some control parameters on the actively controlled sound field near the top edge of noise barriers are studied. Results of numerical study and model measurements are shown and discussed.