Sound propagation models

The Institute of Atmospheric Physics develops and operates advanced sound propagation models. In combination with meteorological mesoscale and microscale models they describe the system of atmosphere, topography and sound waves in a consistent manner. The models are used for scientific studies of the influence of complex terrain and topographical features (valleys, street canyons, vegetation, etc.) under realistic meteorological conditions. They can be used to optimize noise protection measures. Moreover, the models can be used to derive simplified noise prediction procedures.

Two different types of sound particle models are currently in use: 

  • The Linearized Euler (LE) Finite-Difference Time-Domain (FDTD) model AKU3D is based on the prognostic equations for the sound pressure and the sound velocity components. They are numerically solved with higher order procedures. The model optionally considers meteorological effects (mean flow and temperature, turbulent fluctuations), orographic effects, totally or partly reflecting obstacles, and impedance ground.
  • The Langrangian sound particle model AKUMET is based on sound ray theory. A large number of sound particles is released at the source. The particles travel along curved sound rays and carry sound energy into the model domain. The number of particle passages is counted in grid cells to determine the local sound level. In the case of a coherent source the wave length and phase are additionally evaluated. The model optionally considers meteorological effects (mean flow and temperature, turbulent fluctuations), orographic effects, totally or partly reflecting obstacles, and impedance ground.

The sound propagation models are used mainly in the context of traffic noise or the sound of wind turbines.