Simulating complex noise barrier reflections

Within the EU FP7 QUIESST project, QUIeting the Environment for a Sustainable Surface Transport, a test method is being developed for the reflectivity of noise barriers. The method needs to account for a complex shape of barriers and the use of various types of absorbing materials. The performance of a barrier is to be measured in the near field, whereas the far field effects will be used to define an appropriate indicator for the rating of the noise barrier reflecting characteristics. In this QUIESST work package, numerical simulations in the time domain as well as the frequency domain have been used and are compared. This paper presents a method to relate the near field and far field simulations. At the moment near field simulations are used whereas near field measurements will be used in the future. Validation of the method is foreseen by means of measurements in the near and far field. Further, an engineering computation method will be developed as well as an indicator for rating the reflectivity of noise barriers.