A linearized Euler finite-difference time-domain sound propagation model with terrain-following coordinates

The equations of a linearized Euler finite-difference time-domain model for sound propagation through an inhomogeneous and moving atmosphere above absorbing ground are adapted to terrain-following coordinates. With the transformed numerical grid the effect of gentle orography is fully considered and the shortcomings of the representation of the orography by blocked-out grid cells in an untransformed grid are avoided. Comparisons with an analytical method to predict the interference patterns of a monochromic sound field above an idealized hill with rigid ground show good agreement. Further applications include absorbing ground and wind. A three-dimensional application also is discussed.