Prediction models for sound leakage through noise barriers

Two numerical models are presented for the prediction of sound leakage through openings in thin hard barriers. The first numerical method is based on a simple procedure of numerical integration that can be implemented straightforwardly. This model is a more general approach, suitable for barriers with 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 barrier is calculated by a closed-form analytic expression. The total sound-pressure level is determined from a sum of these diffracted fields. Hence, the new method is fast, simple, and intuitive, allowing the leakage to be assessed accurately. The validity of these two numerical models is confirmed by precise experimental measurements.