Sound propagation over layered poro-elastic ground using a finite-difference model

This article presents an axisymmetric pressure-velocity finite-difference formulation (PV-FD) based on Blot's pore-elastic theory for modeling sound propagation in a homogeneous atmosphere over layered pore-elastic ground. The formulation is coded in a computer program and a simulation of actual measurements from airblast tests is carried out. The article presents typical results of simulation comprising synthetic time histories of overpressure in the atmosphere and ground vibration as well as snapshots of the response of the atmosphere-ground system at selected times. Comparisons with the measurements during airblast tests performed in Haslemoen, Norway, as well as the simulations by a frequency-wave number FFP formulation are presented to confirm the soundness of the proposed model. In particular, the generation of Mach surfaces in the ground motion, which is the result of the sound speed being greater than the Rayleigh wave velocity in the ground, is demonstrated with the help of snapshot plots. (C) 2000 Acoustical Society of America. [S0001-4966(00)04008-X].