Experimental characterization of a car window excited by turbulent flow using sound intensity
Reducing the aerodynamic noise produced by turbulent flow exciting a car window is one of the current noise control challenges in the automotive industry. Flow separation and later reattachment into a turbulent boundary layer and turbulent wake occur because of flow over the A-pillar and the wing mirror. Experiments have been carried out to represent an idealised wing mirror noise problem using flow over a half cylinder exciting a flat plate. A scanning P-U (pressure-particle velocity) probe was used to measure various aspects of the window response and sound radiation, including the energy distribution of the vibrating surface, the total radiated sound power and hence the radiation efficiency. In addition, experimental results showed that the operational deflection shapes of the car window can be visualized by using scanning particle velocity measurements, obtaining similar results as with step-by-step measurements using a roving accelerometer. The scanning sound intensity maps also proved to be helpful for detecting weaknesses of the initial experimental setup as part of the experimental optimization.
Fernandez Comesaña, D., Latorre Iglesias, E., Smith, M. and de Bree, H.E., 2012, August. Experimental characterization of a car window excited by turbulent flow using scanning sound intensity techniques. In ASME 2012 Noise Control and Acoustics Division Conference at InterNoise 2012 (pp. 269-277). American Society of Mechanical Engineers.