Overview of Nearfield Acoustical Holography Technologies

This paper describes how nearfield acoustical holography (NAH) allows for reconstructing acoustic quantities such as the acoustic pressure, intensity, and power radiated from a finite object into 3D space based on the acoustic pressures measured on 2D surface. Since NAH provides complete acoustic information cost effectively, it has drawn a great deal of attention in the diagnostics of noise and vibration sources. Three major NAH methods are reviewed and their advantages and disadvantages are compared. While planar NAH is easy to implement, its applications are limited to planar surfaces in a free field only. The Inverse Boundary Element Method (IBEM) is suitable for an arbitrary source surface, but it is difficult to implement due to its strict requirements and intensive computations. The Helmholtz Equation Least Squares (HELS) provides a compromise in reconstruction of acoustic radiation from an arbitrary object by providing an approximate solution using the fewest measurements. Moreover, it is easy to implement, offers great flexibility in measurements and reconstruction, and is very fast. As such, it enables one to obtain a satisfactory reconstruction in the most cost-effective manner.

• Corporate Authors:

  Institute of Noise Control Engineering

  Iowa State University, 210 Marston Hall
  Ames, IA  United States  50011-2153

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Beniwal, Ravinder
  • Mazza, Sergio
  • Moondra, Manmohan S
  • Wu, Sean F
• Conference:
  • Noise-Con 04. The 2004 National Conference on Noise Control Engineering
  • Location: Baltimore Maryland, United States
  • Date: 2004-7-12 to 2004-7-14
• Publication Date: 2004

Language

• English

Media Info

• Media Type: CD-ROM
• Features: Figures; Photos; References; Tables;
• Pagination: pp 76-82
• Monograph Title: Noise-Con 04. The 2004 National Conference on Noise Control Engineering

Subject/Index Terms

• TRT Terms: Acoustics; Damping (Engineering); Environmental impacts; Noise; Noise control; Noise sources; Sound absorption; Sound attenuation; Sound transmission
• Uncontrolled Terms: Nearfield acoustical holography
• Subject Areas: Energy; Environment; Highways; I15: Environment;

Filing Info

• Accession Number: 01054140
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Jul 24 2007 10:56AM