Environmental Noise Mitigation by Plenum Window with Sonic Crystals and Jagged Flap

摘要

A plenum window with incorporation of rectangular sonic crystals (SCs) in between two glass panes was tested in a reverberation room. Before the start of the experiment, numerical studies were performed on the whole structure in order to prove the effectiveness of the SCs in enhancing the noise attenuation performance of the plenum window. The effects of flat and jagged flaps on reducing strength of diffracted sound were also investigated in the experimental studies. White, traffic and construction noises were examined during each measurement. When the frequencies were ranging from 100 Hz to 5000 Hz, the plenum window with SCs without flap was able to attenuate 9.5, 8.5 and 8.6 dBA of white, traffic and construction noises, respectively, compared with the case of without window. The effects of flat flaps on noise attenuation performance of the plenum window were negligible while the jagged flap was able to attenuate additional 1.7 dBA of white noise and 1.6 dBA of traffic and construction noises compared with the case of without flap. In the narrow frequency range of 900-1300 Hz, the plenum window with SCs without flap was able to reduce additional 2.7, 2.3 and 2.5 dBA of white, traffic and construction noises, respectively, compared with the case of without SCs.