Sound Intensity in Atmospheric Shadow Zones Assuming a Constant Velocity Gradient.
Abstract
A simplified mathematical model is completed which will give the shadow zone sound intensities in a medium similar to the earth's atmosphere. The assumed medium is an infinite fluid half-space in which the sound velocity decreases linearly with distance from a rigid plane surface. This model can now be extended to include new meteorological variables, such as wind and temperature gradients and variable sound velocity gradients. A%NALYTICAL SOLUTIONS ARE OBTAINED FOR THE VELOCITY POTENTIAL INTEGRALS FOR SOUND PROPAGATION ABOVE AND BELOW THE POINT SOURCE. A method is developed for calculating the small and large zeros of complex Bessel expression I%( X) + 2 x I3 (x) for generally complex order and argument. The intensity solution is an infinite sum of residues which converges rapidly at the shadow boundary and gives much smaller intensities inside the shadow zone. Large-scale plots of the sound field illustrate some characteristics of the shadow zones. Tables of the residues are reported, containing the first fifty terms in the series solution at several points of the sound field. Values of JK(z) + <ZJ'(z) for large real and complex order are also tabulated. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1970
- Accession Number
- AD0728836
Entities
People
- Phillip H. Duran
Organizations
- University of Texas at El Paso