Abstract
Keywords - HVAC, noise, measurement, FRF, spherical-source
Abstract - As a result of the improvement of interior noise performance of vehicles, the HVAC noise is becoming the main source of noise under client operation conditions. Controlling the HVAC noise during the development of a vehicle is nowadays an usual target for the acoustics engineers.
The standard development processes do not allow a representative frequential evaluation of HVAC noise inside a prototype until the late phases of a project and subsequently, the main part of this acoustic validation is done by bench measuring.
This papers shows that the ventilation noise inside a vehicle could be modelled, under some conditions, by a simple system of spherical acoustic volume velocity sources, located at the centre of the air registers, coupled with the frequency response functions (pressure/volume velocity) between this sources and a reference point in the cabin.
The aim of this kind of model is to provide an accurate model to predict the noise spectrum from bench measurements coupled with frequency response functions calculations or measurement database. This model would avoid the problems of late availability of vehicles mock-ups and it would also allow to define specifications for the suppliers non dependant on cabin environment.