Accession Number:

AD0679673

Title:

Systematic Errors in Ultrasonic Propagation Parameter Measurements. Part 4: Effect of Finite Thickness Elastic Solid Tubes Enclosing the Liquid Cylinder of Interest

Descriptive Note:

Technical Report

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC WASHINGTON United States

Personal Author(s):

Report Date:

1968-11-15

Pagination or Media Count:

143.0

Abstract:

The exact formulation of the characteristic or frequency equation for an inviscid liquid cylinder radially enclosed within a finite impedance elastic solid of finite wall thickness is solved for the permissible modes, including degenerations to the surrounding medium being of infinite extent and either an elastic solid or another liquid, as well as to the limiting cases of infinite impedance rigid boundary and zero impedance free boundary. These modes are utilized to expand both the potential within the otherwise unterminated cylinder and the source impedance variation with position of an opposing termination. A piston source of appreciable ka 100 pi is found to render further source specification indifferent as to uniform pressure or uniform velocity, and a large radial impedance mismatch 28 is found to permit a simplifying orthogonality assumption. With the inviscid assumption, the formulation indicates that a judicious selection of experimental configuration can limit diffraction propagation uncertainties to a few parts per million. An incidental result is the demonstration that the zero elastic tube mode exists at all frequencies rather than displaying an upper cutoff frequency as was recently reported.

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE