## 2aUW4. Poroacoustic media.

### Session: Tuesday Morning, May 14

### Time: 9:20

**Author: Michael D. Collins**

**Location: Naval Res. Lab., Washington, DC 20375**

**Author: William L. Siegmann**

**Location: Rensselaer Polytechnic Inst., Troy, New York 12180**

**Abstract:**

Some poroelastic sediments have relatively high slow-wave speeds and low
shear-wave speeds [N. P. Chotiros, J. Acoust. Soc. Am. 97, 199--214 (1995)].
Wave propagation in these kinds of sediments may be modeled efficiently by
neglecting shear waves to obtain the equations of motion of poroacoustic media.
With this approach, the number of equations is reduced and numerical
implementations may use larger grid spaces. Poroacoustic waves satisfy two
coupled equations. Poroelastic waves satisfy three coupled equations for
two-dimensional problems (the original formulation involves four equations). The
equations of poroacoustics are symbolically identical to the equations of
acoustics. The poroacoustic wave equation is a vector generalization of the
variable density acoustic wave equation [P. G. Bergmann, J. Acoust. Soc. Am. 17,
329--333 (1946)]. The interface conditions between poroacoustic layers are
vector generalizations of the interface conditions between fluid layers. The
energy flux integral of poroacoustics is a vector generalization of the energy
flux integral of acoustics. The equations of motion are in a form suitable for
factoring and solving with parabolic equation techniques. [Work supported by
ONR.]

from ASA 131st Meeting, Indianapolis, May 1996