Sound Wave Diffraction at the Edge of a Sound Barrier

• Authors: J. Piechowicz
• Languages of publication: EN

Abstracts

EN

The diffraction phenomenon is described by the Huygens-Fresnel principle. The review of physical laws ruling the bending of sound waves at the edge of the screen allows the effective selection of both acoustical and geometrical parameters of the screen. Sound wave diffraction theories have been developed on the basis of wave optics, when wavelength is small in comparison to the size of the obstacles, which can be also used in acoustics with the same assumptions about geometry of the system. Diffraction can be seen as a result of the interference of waves reaching the point of observation in accordance with the laws of geometrical optics and wave disturbances arising as a result of interaction with the edge of an obstacle. The paper describes a test method using maximum length sequences for determining the intrinsic characteristics of sound diffraction in situ during testing of roadside noise barriers. A scale model experiment has been performed in an anechoic room. Also, a real noise reducing device was tested in free field conditions.

Keywords

EN

43.20.El; 43.20.Fn; 43.50.Gf; 43.50.Yw; 43.60.Ek; 43.55.Rg

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2011
• Volume: 119
• Issue: 6A
• Pages: 1040-1045

Dates

published

2011-06

Contributors

author

J. Piechowicz

• Department of Mechanics and Vibroacoustics, AGH - University of Science and Technology, al. A. Mickiewicza 30, 30-059 Kraków, Poland

References

• 1. W. Rubinowicz, Adv. Phys. 21, 161 (1970) (in Polish)
• 2. Z. Engel, J. Sadowski, M. Stawicka Wałkowska, S. Zaremba, Noise Barriers, AGH, Kraków 1990 (in Polish)
• 3. J.B. Keller, J. Opt. Soc. Am. 62, 116 (1962)
• 4. P.B. Sunil Kumar, G.S. Ranganath, Current Sci. 61, 10 (1991)
• 5. D.A. McNamara, C.W.I. Pistorius, J.A.G. Malherbe, Introduction to the Uniform Geometrical Theory of Diffraction, Artech House, Norwood 1990
• 6. M. Garai, P. Guidrzi, in: Proc. 19th Int. Congress on Acoustics, Madrid, 2007, CD
• 7. CEN/TS 1793-4 Road traffic noise reducing devices - Test method for determining the acoustic performance - Part 4: Intrinsic characteristics - in situ values of sound diffraction
• 8. H. Tachibana, in: Proc. 39th Int. Congress on Noise Control Engineering, Lisbon, 2010, CD

Identifiers

DOI

10.12693/APhysPolA.119.1040