Sound Propagation through a Turbulent Atmosphere: Experimental Techniques and Data Analysis
Abstract
Propagation of sound waves close to the ground is a complex problem involving many interesting mechanisms. In addition to geometrical spreading and molecular absorption, which are reasonably well understood, the three main mechanisms which influence the acoustic field are reflection with phase change due to the finite impedence of the ground, refraction by wind and temperature gradients, and scattering by atmospheric turbulence. Outdoor sound propagation in a turbulent medium is not a well understood process and has only recently begun to receive serious attention. This report is the first of a series of reports on sound propagation through a turbulent atmosphere. It documents the experimental configuration and describes data analysis. The data analysis includes plots of the real and imaginary parts of the acoustic pressure as a function of time (scatter plots), probability of observing a particular amplitude, and the more familiar structure functions. A preliminary analysis of data suggests reasonable agreement in structure functions at frequencies of 500 Hz and above. At lower frequencies, phase and log amplitude structure functions are both larger than predicted from theory. A tentative explanation for this difference is under development and will be presented in the third of the three volume series. The second volume will be devoted to refractive effects. Keywords: Computer programs; Outdoor sound.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 19, 1987
- Accession Number
- ADA188891
Entities
People
- Henry E. Bass
- John Noble
- Lee N. Bolen
Organizations
- University of Mississippi