### ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

## 1aPA9. Application of the PE method to up-slope sound propagation.

**Marta Galindo
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Karsten Bo Rasmussen
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*Acoust. Lab., Bldg. 352, Tech. Univ. of Denmark, DK 2800 Lyngby, Denmark
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The wide-angle PE method is applied to the prediction of sound propagation
in a range-dependent environment. The finite-difference model treats the
sloping ground by a staircase approximation. The method allows impedance and
slope angle variations to be taken into account. The implementation of sloping
interfaces in one-way PE models introduces a fundamental problem of energy
conservation. This is generated at the lower boundary condition. The ground is
assumed to be a locally reacting surface where the ground impedance is defined
as the ratio of pressure to the normal component of particle velocity at the
surface. The staircase PE method approximates the normal at the slope surface
with the vertical component at the stair-step surface. A numerical correction
can be included. Using a scale model facility [K. B. Rasmussen,
3617--3620 (1994)], a series of measurements is carried out. The results are
compared with the PE calculations. The magnitude of the error due to the
interface condition is evaluated.