Lowfrequency sound propagation modeling over a locallyreacting boundary using the parabolic approximation
Abstract
There is substantial interest in the analytical and numerical modeling of lowfrequency, longrange atmospheric acoustic propagation. Raybased models, because of frequency limitations, do not always give an adequate prediction of quantities such as sound pressure or intensity levels. However, the parabolic approximation method, widely used in ocean acoustics, and often more accurate than ray models for lower frequencies of interest, can be applied to acoustic propagation in the atmosphere. Modifications of an existing implicit finitedifference implementation for computing solutions to the parabolic approximation are discussed. A locallyreacting boundary is used together with a oneparameter impedance model. Intensity calculations are performed for a number of flow resistivity values in both quiescent and windy atmospheres. Variations in the value of this parameter are shown to have substantial effects on the spatial variation of the acoustic signal.
 Publication:

Unknown
 Pub Date:
 August 1989
 Bibcode:
 1989lfsp.rept.....R
 Keywords:

 Finite Difference Theory;
 Low Frequencies;
 Mathematical Models;
 Sound Propagation;
 Atmospheric Effects;
 Sound Pressure;
 Acoustics