دانلود رایگان مقاله روش ماتریس انتقال برای تضعیف صدا در رسنترس

Abstract

A resonator with perforated intruding inlet (PII) is a superior silencer element, since the use of perforated inlet extensions can dramatically improve the acoustic performance. In this work, both a one-dimensional (1D) and a two-dimensional (2D) transfer matrix methods are developed to predict the transmission loss of the resonator without considering the mean flow. Based on the two groups of comparisons with tests, it is found out that the applicability of 1D method is limited by the resonator geometry even when the frequency is below the cut-off value of plane wave. Whereas the 2D approach is much more accurate while predicting the transmission losses within entire frequency range. Subsequently, five groups of resonators are chosen to determine the effects of structure parameters to transmission loss based on the 2D approach. The resonant frequency decreases and more resonant peaks appear when the length of inlet extension increases. A higher perforation rate leads to a shift of resonant peak towards higher frequencies. Besides, better acoustic performance could be obtained with the perforation being properly designed. Reducing the inlet/outlet radius can obviously improve the transmission loss without changing the frequency of resonant peak. The theories and conclusions in this study can be used for the design and optimization of resonators in various engineering applications.

5. Conclusions

In this paper, both 1D and 2D approaches are applied to predict the acoustic performance of a resonator with PII. Based on a previous mathematical model, a 1D TMM without considering the mean flow is derived. However, through two groups of comparisons with tests, it is concluded that the applicability of 1D TMM is limited by the resonator geometry even when the frequency is below the cutoff value of plane wave. Obvious deviations will occur if the chamber length becomes short, and additional end corrections may be necessary. In comparison, TLs calculated by the 2D TMM, which is as timesaving as 1D approach match well with that of FEM, and show a good agreement with the tests. Hence, the 2D approach developed in this study is validated to be very accurate and effective in calculating the TLs of resonators with PII.