Accession Number : ADA305929

Title :   The Solution for the Propagation of Sound in Cylindrical Tubes and Toroidal Waveguides with Driven Walls.

Descriptive Note : Final rept. 1 Jul 92-299 Sep 95,

Corporate Author : NATIONAL CENTER FOR PHYSICAL ACOUSTICS UNIVERSITY MS

Personal Author(s) : Lawrenson, Christopher C. ; Shields, F. D.

PDF Url : ADA305929

Report Date : 18 MAR 1996

Pagination or Media Count : 200

Abstract : This dissertation is a theoretical and experimental study of sound in tubes with driven (or active) walls. Two geometries are considered: (1) a cylindrical tube of infinite length, and (2) a toroidal waveguide. For sound propagation in the first geometry, two cases are theoretically considered. The first case is that of a lossless fluid, and the second is a viscous and thermally conducting fluid. The derivation of the latter case closely follows Lord Rayleigh's derivation of sound propagation in a rigid tube. Theoretical results for the particle velocity components of both cases are presented along with the three modes of propagation found in the second case. For sound propagation in the second geometry, the cases of rigid and driven wall toroids with lossless fluids are presented, along with methods for including losses in the system. Theoretical results for the pressure inside the toroid with various driving conditions and parameters are shown. Experimental measurements of the sound pressure levels in a toroid are presented and compared to theoretical results. To make some of these measurements, it was necessary to develop a device we are calling an acoustitron. Results show that the physical system is well represented by the theory presented in this work.

Descriptors :   *SOUND TRANSMISSION, *TUBES, EXPERIMENTAL DATA, THESES, WAVEGUIDES, CYLINDRICAL BODIES, ACOUSTIC MEASUREMENT, TOROIDS, GEOMETRY, WALLS, FLUIDS, RIGIDITY, SOUND PRESSURE, TRANSMISSION LOSS.

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE