Modeling and Computation of Plate Resonator Silencers

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Silencers are components or devices that hinder the propagation of sound in flow channels. Thus, they are crucial for noise control at the propagation path and are used for very different applications such as noise reduction in aircraft engines, in ventilation and air conditioning systems, in exhaust systems of engines and gas turbines and many more. There are several working principles, all of which produce frequency-dependent transmission loss. For most applications, transmission loss over a wide frequency range is important. Presently, however, efficient broadband sound attenuation at low frequencies is a major challenge. Substantial concession in terms of the required size, the influence on the flow in the channel and the costs are always necessary.The main objective of the project is to gain a precise understanding of the operation of silencers, where plate resonators are used as sound-damping linings in flow channels. Unlike many other concepts, they offer a closed, smooth surface and show a good performance at low frequencies. If properly designed they may offer a broadband sound attenuation at the same time. However, up to now the design of such silencers is on an empirical basis. It is therefore desirable to develop an analytical calculation model that uncovers the underlying working principles and parameter dependencies and thereby allows a targeted design and full use of the potential of such mufflers. Furthermore, multilayer plate resonators will be investigated to find out if and to what extent adjacent or multilayer, differently tuned plate resonators can improve the transmission loss. Finally, it is intended to model the influence of the flow on the effectiveness of the plate resonator silencers. The analytical calculation model is to be validated on the basis of measurement data as well as results of a much more computationally expensive numerical model.The significance of the project is to develop a possibility of a precise, targeted design of plate resonator mufflers, which can primarily open up new applications of silencers where previously sound attenuation with conventional concepts was not or only partially possible. This also makes other, non-acoustic advantages of this silencer concept available.