Accession Number : AD0836045

Title :   CALCULATION OF ACOUSTIC FIELDS ABOUT ARBITRARY THREE-DIMENSIONAL BODIES BY A METHOD OF SURFACE SOURCE DISTRIBUTIONS BASED ON CERTAIN WAVE NUMBER EXPANSIONS.

Descriptive Note : Final technical rept.,

Corporate Author : DOUGLAS AIRCRAFT CO LONG BEACH CA

Personal Author(s) : Hess, John L.

Report Date : 15 MAR 1968

Pagination or Media Count : 256

Abstract : This report describes a method for calculating, with the aid of a large-scale computer, the steady acoustic field about an arbitrary three-dimensional body. The method utilizes a source density distribution on the surface of the body and solves an integral equation to obtain the specific distribution required to meet the boundary condition. The method is applicable to any body and boundary condition, but is subject to a frequency limitation that in practice limits the applicability of the method to frequencies below a certain range that depends on body shape. In the report the basic formulas of the method are derived, and the computational procedure is described in detail. The accuracy of the method is exhibited by comparing its calculations with analytic solutions for a variety of body shapes, boundary conditions, and sound frequencies. (Author)

Descriptors :   (*THREE DIMENSIONAL FLOW, PROBLEM SOLVING), ACOUSTIC PROPERTIES, GEOMETRIC FORMS, DENSITY, SURFACE PROPERTIES, INTEGRAL EQUATIONS, BOUNDARY VALUE PROBLEMS, FREQUENCY, CORRELATION TECHNIQUES, SCATTERING, ACOUSTIC IMPEDANCE, DIGITAL COMPUTERS.

Subject Categories : Acoustics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE