Evaluation of the Biot Coefficients.

Abstract

The Biot equations are the most promising approach for modeling the propagation of acoustic waves in ocean sediments. A method has been developed by Bedford, Costley and Stern for determining the drag and virtual mass coefficients in Biot's equations as functions of frequency. The method requires solving for the motion of the fluid in the pores when the pore walls are subjected to a spatially uniform, oscillatory motion. In this project, a finite element algorithm has been developed to determine the fluid motion. The accuracy of the model has been verified using a model problem for which exact results could be obtained. The drag and virtual mass coefficients have been determined for several two dimensional pore spaces. It has been determined that the drag coefficient is insensitive to the pore geometry while the virtual mass coefficient is very sensitive to the pore geometry. It has also been shown that the coefficients can be expressed in nondimensional forms which permit their values to be scaled for different values of a characteristic linear dimension of the pore space. This project has established a firm basis for proceeding to determine the coefficients for three dimensional pore spaces.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1987
Accession Number
ADA191643

Entities

People

  • A. Bedford
  • B. Yavari

Organizations

  • University of Texas at Austin

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Acoustic Waves
  • Boundary Value Problems
  • Computations
  • Elastic Waves
  • Equations
  • Finite Element Analysis
  • Fluid Mechanics
  • Frequency
  • Geometry
  • Mach Number
  • Materials
  • Mechanics
  • Phase Velocity
  • Steady State
  • Three Dimensional
  • Two Dimensional
  • Waves

Readers

  • Calculus or Mathematical Analysis
  • Finite Element Method (FEM) for solving Partial Differential Equations (PDEs)
  • Materials Science and Engineering.

Technology Areas

  • Space
  • Space - Hall-Effect Thruster
  • Space - Orbital Debris