Volume 127, Issue 1, January 2010
Index of content:
- GENERAL LINEAR ACOUSTICS 
127(2010); http://dx.doi.org/10.1121/1.3263613View Description Hide Description
The dispersion relation for seismoelectric wave propagation in poroelastic media is formulated in terms of effective densities comprising all viscous and electrokinetic coupling effects. Using Helmholtz decomposition, two seismoelectric conversion coefficients are derived, for an incident P-wave upon an interface between a compressible fluid and a poroelastic medium. These coefficients relate the incident P-wave to a reflected electromagnetic wave in the fluid, and a transmitted electromagnetic wave in the porous medium. The dependency on angle of incidence and frequency is computed. Using orthodox and interference fluxes, it is shown that energy conservation is satisfied. A sensitivity analysis indicates that electrolyte concentration, viscosity, and permeability highly influence seismoelectric conversion.
127(2010); http://dx.doi.org/10.1121/1.3268606View Description Hide Description
A widely employed description of the acoustical response in a cavity whose walls are compliant, which was first proposed by Dowell and Voss [(1962). AIAA J.1, 476–477], uses the modes of the corresponding cavity with rigid walls as basis functions for a series representation of the pressure. It yields a velocity field that is not compatible with the movement of the boundary, and the system equations do not satisfy the principle of reciprocity. The simplified formulation is compared to consistent solutions of the coupled field equations in the time and frequency domains. In addition, this paper introduces an extension of the Ritz series method to fluid-structure coupled systems that satisfies all continuity conditions by imposing constraint equations to enforce any such conditions that are not identically satisfied by the series. A slender waveguide terminated by an oscillator is analyzed by each method. The simplified formulation is found to be very accurate for light fluid loading, except for the pressure field at frequencies below the fundamental rigid-cavity resonance, whereas the Ritz series solution is found to be extremely accurate in all cases.