4. General conclusion

During the 1970s and 1980s, the increase in noise pollution from transport and industry necessitated the improvement in some cases, and the development in more complex cases, of various models for predicting propagative effects at great distances from the source, initially taking into account ground effects and later atmospheric effects.

During this same period, the constant evolution of techniques enabled us to considerably improve theoretical models, so as to come as close as possible to realistic propagation conditions. Thus, the influences of heterogeneous soils and a fluctuating atmosphere were successively identified.

Analytical approaches, mainly based on geometric acoustics, quickly showed their limits as calculation configurations became more complex. Numerical methods then took over. The results presented in this article show that...