Acoustic Modes of a Constricted Annular Resonator. Part (Ⅱ). Experiment

截面積突縮環狀共振器之聲波模態(Ⅱ)．實驗

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. 233-241

https://doi.org/10.30028/CSSVANNUAL.199805.0233

摘要

本文旨在以實驗方式來探討截面積突縮環狀共振器之特性，並將量測結果與理論預估值相比較。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，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拘束處有一速度反節點，實驗所得共振器之聲波模態及共振頻率與理論預估結果相當吻合，吾人並且發現共振器截面積突縮處之尾端修正相當重要而必須納入考量。

並列摘要

The acoustic modes in a constricted annular resonator are investigated experimentally and the finding are compared with those of a theoretical Investigation. The acoustic resonator under study is a air-filled annular aluminum duct. It is shown that introduces a constriction into an annular resonator splits each longitudinal duct mode into two modes. one of a higher frequency with a pressure antinode the constriction and one at a lower frequency with a velocity antinode near the constriction. Overall agreement between measured and predicted mode shapes and resonance frequencies is very good. It was found that it is necessary to include end corrections at the constriction to get accurate agreement between measured and predicted results.