M. West
R. A. Sack
Dept. of Appl. Acoust., Univ. of Salford, Salford M5 4WT, UK
A two-dimensional algorithm based on Gilbert and White's method [West et al., Appl. Acoust. 36, 1--19 (1992)] coded for a 486 PC, has served as a test bed for the following modifications: (i) a new second-order ground boundary condition, (ii) a ``tuned'' upper absorbing layer, (iii) a novel upper boundary condition, which replaces the absorbing layer, and (iv) a new procedure for calculation of the starter field. The algorithm with the above modifications has also been adapted to operate with range-dependent sound-speed profiles obtained from an isoturbulent atmospheric model. [Work supported by MOD and DRA.]