Accession Number : ADA308156

Title :   Nonlinear Acoustics and Shock Waves in Sediments and Fluid-Filled Porous Media.

Descriptive Note : Final technical rept. 1 Jul 94-30 Jun 95,

Corporate Author : RUTGERS - THE STATE UNIV PISCATAWAY NJ COLL OF ENGINEERING

Personal Author(s) : Norris, Andrew N.

PDF Url : ADA308156

Report Date : MAY 1996

Pagination or Media Count : 78

Abstract : Considerable progress has been made in establishing the appropriate master system of equations suitable for modeling shock waves and nonlinear wave phenomena in fluid-permeable porous solids. The major accomplishments are as follows. (1) Numerical experiments establishing the existence of shock waves in a 1D system with both Darcy and Navier-Stokes viscosities. (2) The general form of the equations of motion have been deduced from Hamilton's principle of Least Action combined with Onsager's method of irreversible thermodynamics. (3) We analyzed the specific case of a layered fluid/solid medium in depth, and obtained explicit formulas for the nonlinear strain energy and the permeability operator. (4) We have extended the methods of acoustoelasticity to poroelastic media. (5) We have examined the stability of acoustic disturbances in a simple model of a porous medium with a mean flow through the pores.

Descriptors :   *ACOUSTIC WAVES, *SHOCK WAVES, *EULER EQUATIONS, STRESS STRAIN RELATIONS, MATHEMATICAL MODELS, EQUATIONS OF MOTION, MODULUS OF ELASTICITY, POROSITY, COMPRESSIBLE FLOW, WAVE PROPAGATION, NONLINEAR ANALYSIS, NUMERICAL METHODS AND PROCEDURES, BOUNDARY LAYER TRANSITION, NAVIER STOKES EQUATIONS, VISCOUS FLOW, VISCOSITY, UNDERWATER ACOUSTICS, ACOUSTIC VELOCITY, SEDIMENTS, TRAVELING WAVES, TWO PHASE FLOW, FLUTTER, IRREVERSIBLE PROCESSES, POROUS MATERIALS, GRANULAR MATERIALS, HAMILTONIAN FUNCTIONS, LAGRANGIAN FUNCTIONS, STEADY FLOW.

Subject Categories : Acoustics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE