Experimental Method to Measure Low Frequency Sound Radiation - Nearfield Acoustical Holography.
Abstract
A technique called Nearfield Acoustical Holography (NAH) has been developed. The technique, a significant improvement over conventional holography, is not subject to the wavelength resolution limitation associated with conventional techniques. An exact formulation of the Green's function propagator allows reconstructions of the entire pressure, particle velocity, and vector intensity fields. The vector intensity may be plotted to show the flow of acoustic energy around and away from a source. On some sources, these mappings reveal areas of non-radiating, circulating energy flow. These areas may have large pressure or velocity amplitudes and negative intensity regions that previously led to misconceptions about the production of acoustic energy.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 03, 1982
- Accession Number
- ADA114777
Entities
People
- William Y. Strong Jr
Organizations
- Pennsylvania State University