On-Going ISL Research in Modeling Acoustic Propagation in the Atmosphere

Atmospheric boundary layer processes, like wind, stratification, or turbulence, strongly affect the acoustic propagation. In the context of sensor development, they must be accounted for, to determine the effective sensor performance. Field experiments are the essential method to derive these sensitivities. However they face high costs and the difficulty of measuring the many relevant parameters. Hence realistic modeling of acoustic propagation is a very useful complement. In the last decades, the research Institute Saint-Louis (ISL) has developed and used some modeling tools that can handle the impact of a mean atmospheric stratification. Modeling the acoustic propagation in the time domain is a recent development, still computationally intensive, which further enables to deal with turbulence and obstacles. This method has been developed at ISL following Wilson and Liu (2004). The results can be compared with other codes in standard benchmark cases. Sensitivity to atmospheric features can then be analyzed by off-line coupling with atmospheric models. A difficulty there is to model the atmospheric features at the adequate resolution. ISL efforts in that direction are based on synthetic fluctuations generation and Large-Eddy Simulation. Preliminary tests will be presented, including the impact of turbulence on acoustic propagation.