Investigations into the attenuation by screens under the influence of wind

A simple hard screen on an absorbing ground is investigated experimentally and theoretically under upwind conditions. The experimental data are the result of model experiments in a 1:25 scale model within a wind tunnel. The sound propagation is measured using a triggered spark source and averaging on power basis in the frequency domain. The meteorological data representing the wind conditions have been determined by means of hot-wire anemometry in positions on both sides of the screen as well as directly over the screen. The theoretical model used for comparison is a hybrid approach. The sound field without a barrier is determined by means of numerical integration of a Hankel transform solution for a stratified atmosphere. This solution is used for propagation from source to screen and from screen onwards. The screen is taken into account by means of diffraction theory. Comparison of theoretical and experimental data shows a good agreement for upwind propagation. For downwind propagation the sound is carried over the screen in a manner which the present approach is unable to predict.