Effective acoustic equations for a two-phase medium with microstructure

  • Authors:
  • R. P. Gilbert;A. Panchenko

  • Affiliations:
  • -;-

  • Venue:
  • Mathematical and Computer Modelling: An International Journal
  • Year:
  • 2004

Quantified Score

Hi-index 0.98

Visualization

Abstract

We study acoustic wave propagation in a two-phase medium in which the solid phase is a linear elastic material, and the fluid phase is assumed to be a compressible Newtonian barotropic fluid. Assuming that properties of the medium change rapidly on the small scale @e, we analyze the microscopic nonlinear Navier-Stokes equations and show that they can be linearized when @e tends to zero. Using a variant of Tartar's method of oscillating test functions, we derive effective acoustic equations which turn out to be viscoelastic. In order to treat disordered materials occurring in nature, we develop a new approach to describing geometry of a nonperiodic medium with length scale separation. Our approach is not based on probabilistic considerations. Instead, we postulate that certain inequalities hold uniformly on the microscale.