Accession Number:

ADA106349

Title:

Approximate Fluid-Structure Interaction Theories for Acoustic Echo Signal Predictions.

Descriptive Note:

Final rept.,

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s):

• Huang,H.

Report Date:

1981-10-19

Pagination or Media Count:

17.0

Abstract:

An approximate scheme for predicting the acoustical echo signals from submerged elastic structures irradiated by incident pulses is proposed and investigated for its effectiveness. This scheme utilizes various approximate fluid-structure interaction theories to first determine the resultant pressure and normal acceleration on the fluid-structure interface and therefrom calculates the far field echo signals by integrating the Helmholtz integral exactly. It is found that a theory termed the second order doubly asymptotic approximation is promising for this scheme. An optimum computation scheme could be a combination of the exact and various approximate theories depending on the wavelength of the incident pulse and the geometry and the dynamic characteristics of the structure. Author

Descriptors:

• *TARGET STRENGTH
• *SONAR TARGETS
• EQUATIONS OF MOTION
• ELASTIC PROPERTIES
• MATHEMATICAL PREDICTION
• STRUCTURAL RESPONSE
• APPROXIMATION(MATHEMATICS)
• ASYMPTOTIC SERIES
• ACOUSTIC SCATTERING
• SONAR ECHOES
• ECHO RANGING
• WAVE EQUATIONS

Subject Categories:

• Acoustic Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE