Acoustic Modes of a Constricted Annular Resonator. Part (Ⅰ). Theory

截面積突縮環狀共振器之聲波模態(Ⅰ)．理論

林筱增(Hsiao-Tseng Lin)

《中華民國振動與噪音工程學會論文集》 1998 (1998/05) Pp. 225-231

https://doi.org/10.30028/CSSVANNUAL.199805.0225

摘要

環狀熱聲原動機為目前熱聲學研究的一個主題，此研究肇始於一截面積突縮環狀共振器之特性探討。本文提出此類共振器之理論研究及數值分析，結果顯示將環狀共振器一部份截面積突縮將使共振器原有的縱向模態分離成兩個不同頻率之模態。這種頻率分離的現象可在其他領域中發現，其中較高頻率之模態在截面積突縮處有一壓力反節點，而較低頻率之模態在截面積突縮處有一速度反節點，前者對截面積突縮長度及開孔度之反應較後者明顯。

並列摘要

One topic of current interest in thermoacoustic research is an annular prime mover [1]. The starting point for this research is an investigation of a constricted annular resonator. The results of analytic and numerical investigations are presented. Introducing a constriction into an annular resonator splits each longitudinal duct mode into two modes, one of a higher frequency with a pressure antinode at the constriction and one at a lower frequency with a velocity antinode near the constriction. This frequency splitting phenomenon can be found in different fields. The lower mode is more sensitive to changes in the length and porosity of the constriction than the higher mode.