Prediction models for sound leakage through noise barriers

Two numerical models are presented for the prediction of sound leakage thro ugh openings in thin hard barriers. The first numerical method is based on a simple procedure of numerical integration that can be implemented straigh tforwardly. This model is a more general approach, suitable for barriers wi th arbitrary gaps. The second model is a new method that permits prediction of sound leakage due to the presence of horizontal gaps in a long barrier. In the new method, effective barriers of appropriate heights represent the edges of the horizontal gaps. The sound diffracted by each effective barri er is calculated by a closed-form analytic expression. The total sound-pres sure level is determined from a sum of these diffracted fields. Hence, the new method is fast, simple, and intuitive, allowing the leakage to be asses sed accurately. The validity of these two numerical models is confirmed by precise experimental measurements. (C) 2001 Acoustical Society of America.