Edge diffraction in a multireflective environment: Measured and calculatedinsertion loss of a retained cut

A side benefit of funnelling through traffic into underground tunnels and/o r depressed roads is a certain degree of noise shielding for the nearby are as. Roads located in a cutting in the ground have received specific attenti on as a measure for controlling traffic noise propagation. This paper repor ts a study aimed at the validation of a numerical model for the insertion l oss (re free field) of a retained cut. The computerized procedure Is based on the combination of a complex image model and a model for evaluating the field diffracted by the edge of a sound-absorbing wedge. Measurements were carried out in a reduced scale physical model of a retained cut and results are compared with the numerical prediction. The experimental results are i n a fairly good agreement with the calculated ones. (C) 1999 Institute of N oise Control Engineering. [S0736-2501(99)00201-5].