Approximate Fluid-Structure Interaction Theories for Acoustic Echo Signal Predictions

摘要

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)