Prediction of acoustic fields radiated into a damped cavity by an N-port source through ducts

The use of two parameters—source impedance and source strength—to model a fluid machine radiating fluid-borne sound via ducts has led to excellent predictions when the source, a ventilator, propagates in one or two plane-wave ducts. Can such previously published methods successfully be applied to the case of a multi-port source radiating via ducts into a damped cavity? The case under study here is a car ventilation/heating unit and the aim was to predict the pressure spectrum inside the passenger compartment caused by the noise propagated through the ventilation ducts. The progressive validation procedure used indicated how and why as the system increases in complexity, predictive accuracy diminishes. The final results are nevertheless convincing and the hypotheses, which can be further refined to reflect the reality better and provide higher quality results, are clearly defined.