Experimental Investigation of Sound Power Radiation From Partly Open Enclosure With Numerous Interior Objects
Paper in proceedings, 2007

The radiated sound power from an engine of a passenger car is highly dependent on the acoustical properties of the engine bay. The engine bay is a densely packed and partly open enclose where standard room acoustics models do not directly apply. It has a complex geometry of numerous accessory parts, cables, pipes, screens, and absorbers that all together affect the wave field and the radiated sound power. Radiated sound power from a simplified hardware model has been measured for various configurations of interior objects. The measurements have been preformed in an anechoic environment using a reciprocal technique where source and receiver positions are interchanged. The results show a clear tendency with higher reduction of the radiated sound power at higher frequencies as the number of objects is increased. There is a reduction of about 10 dB at higher frequencies when 10% of the empty volume is filled with objects. Screens partly covering openings are needed in the modal range to get a significant reduction. Differences in sound radiation between specific source positions show clear variations. Models combining deterministic and statistical approaches are needed to cover the local behaviour in a wide frequency range.

Author

Eskil Lindberg

Chalmers, Civil and Environmental Engineering, Applied Acoustics, Vibroacoustics

Patrik Andersson

Chalmers, Civil and Environmental Engineering, Applied Acoustics, Vibroacoustics

19th International Congress on Acoustics, Madrid, 2007

Subject Categories

Other Materials Engineering

Fluid Mechanics and Acoustics

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11/21/2018