Colloquia

Summary

The adverse health effects of noise pollution are receiving more attention. Accurate models for long-distance sound propagation are valuable to supplement measurements for the assessment of traffic and industrial noise. The inclusion of atmospheric conditions, like wind and temperature, contributes to the accuracy of these models. The new formulation of the Helmholtz equation in terms of the complex variable ξ, finds accurate solutions on significantly coarser meshes than the classical pressure-based approach. In this report the ξ-formulation is extended to the convected Helmholtz equation and additional atmospheric conditions, such as attenuation and spatially varying density, are incorporated. Previously observed convergence issues, particularly cases involving strong refraction or particle velocity boundary conditions, are investigated. An H1 semi-penalty method is proposed to address refraction-related convergence problems. Challenges related to the particle velocity boundary condition are analysed and partially resolved. The new approach is thoroughly verified for all considered atmospheric conditions.