Modelling of spherical wave reflection on an absorbing flat surface considering its finite size – Application to traffic noise barriers

Journal article, 2026

To improve the modelling of the sound absorption performance of traffic noise barriers, this study investigates the extension of the analytically-based Direct Field Absorption (DFA) model to lower frequencies. The DFA model results are compared with those from Boundary Element Method (BEM) simulations and reflection measurements conducted under controlled conditions using the SOPRA method, developed in the SOPRANOISE project on optimizing the performance of road traffic noise barriers. The paper describes the developed frequency-domain DFA model, the application of BEM, and their application to the SOPRA measurement setup. From the results it is concluded that the DFA model is suitable for predicting noise absorption performance at lower frequencies for enlarged barrier surfaces. Additionally, interference effects between reflected and diffracted components are characterized.