### ASA 127th Meeting M.I.T. 1994 June 6-10

## 2aPA7. Integral formulation of wave propagation through a turbulent
medium.

**Hirobumi Kaneko
**

**
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*Dept. of Aerosp. and Mech. Eng., Boston Univ., 110 Cummington St., Boston,
MA 02215
*

*
*
A novel technique for approximate computation of transient waveforms
through weakly inhomogeneous media is described. It has some of the features of
ray acoustics formulations, but largely circumvents the problems associated
with caustics and allows the incorporation of diffraction effects. The
prototype for a single step in propagation range is that where the acoustic
pressure is specified as a function of time and lateral position on a planar
surface, with the desire to determine the acoustic pressure on some further
surface at a distance (Delta)x in the general direction of propagation. To
determine the pressure versus time at a typical point on the second surface, an
approximate integral solution is developed in terms of a Green's function for a
point source in the inhomogeneous medium. Such a Green's function is determined
by matching a ray acoustics solution in the far field to Blokhintzev's
well-known solution for a point source in a homogeneous moving medium. Although
the overall wave field may encounter a caustic in the intervening slab, such is
not as likely to occur for the Green's function because of its intrinsic
spherical spreading.