Conference_programme: 2.1 - Aeroacoustics
Lecture: Full scale experimental model investigation in an anechoic chamber of the generation of aeolian tones in aerodynamic sound by airflow around glass fins mounted on the façade of the new Headquarters of the Interuniversity Micro Electronics Centre, Leuven, Belgium.
Author(s): Tournoy Dirk
Summary:
Airflow at high speed through small openings or around more or less aerodynamically shaped objects can give rise to sound with tonal components. Shedding vortices develop immediately behind the opening or object. In these vortices sound pulsations are generated. We distinguish two types of aeolian tones. The first type has a frequency directly related to the air flow velocity. It generally occurs at lower frequencies. The second type has a frequency more or less independent on air flow velocity. It occurs at higher frequencies and is generally present along grating structures.\nThe Interuniversity Micro Electronics Centre (IMEC), a world-leading R&D and innovation hub in nanoelectronics and digital technologies with world-class infrastructure, has recently completed its new Headquarters in Leuven Belgium. The façade is built entirely from several metre high windows with glass ‘fins’ providing an attractive play of lines.\nTo prevent any form of annoying aerodynamic noise for both the environment and the occupants of the building, a 1:1 scale model of a façade element was tested in a semi-anechoic chamber. It was found that at high wind speeds of 15m/s or 50km/h and grazing incidence, aeolian tones were generated with a fairly constant frequency between 2 and 2.5kHz. The sound power is independent of the wind speed and the distance between the glass fins and the façade, clearly confirming the repetitiveness of the structure as the noise source. \nSeveral parameters were varied such as wind speed, air gap between glass fins and façade and the shape of the glass fins. In an optimized situation the linear sound power is measured to be LWA=54dB/meter, generating a sound pressure level of Lp=49dBA at 1m distance from the façade. This is considerably lower than the incident traffic noise level on the site of 59-66dBA.
Corresponding author
Name: Mr Dirk Tournoy
e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Country: Belgium
