Acoustic resonators for the reduction of sound radiation and transmission

Noise is a frequently encountered problem in modern society. One of the environments where the presence of noise causes a deterioration in people’s comfort is in aircraft cabins. For modern aircraft flying at cruise conditions, the main sound source is the turbulent boundary layer around the fuselage. Especially in the mid and high frequency range (500-2000 Hz), this source significantly contributes to the sound levels in the aircraft cabin. Passive noise reduction methods can provide a suitable solution to many noise problems in this frequency range. In the present study, a new passive noise reduction method is presented, known as tube resonators. Tube resonators are well-known for their application for sound absorption. However, in the present work, this type of resonator is applied for the reduction of sound radiation and sound transmission. The aim of this work is to investigate the applicability of this new method and to develop and validate efficient models for the prediction of sound radiation by and sound transmission through panels with tube resonators. For a proper understanding of the influences of the different phenomena, different models and experiments are presented in order of increasing complexity.