本研究以實驗方法探討噴流驅動的Helmholtz共振腔，其幾何外形的不同對聲音特性的影響。以圓柱狀厚紙筒及pvc塑膠管，製作出不同形狀的Helmholtz共振腔。實驗內容為觀察圓柱狀Helmholtz共振腔幾個基本形狀參數對聲音特性的影響，包含頸長、高度、口徑、開孔面積、開孔形狀及開孔位置。觀察一些比較特殊外形的Helmholtz共振腔，包含彎圓柱、內外圓柱的組合(套管)、窄口瓶對聲音特性的影響。
實驗結果顯示，除了開孔形狀、開孔面積因振動模態的轉換有所不同外，其他基本參數的變化趨勢大致符合理論公式的趨勢。內外圓柱的組合(套管)可驅動的頻率範圍，會小於等體積的圓柱，且在內圓柱體積占外圓柱的小於50%時，頻率不會高於等體積的圓柱，還有可能變低。彎圓柱在彎曲夾角較大時(135度)，頻率會略低於直圓柱；角度較小時(90度)，頻率會略高於直圓柱，但差異約在10%以下。兩端口徑不同的圓柱(窄口瓶)，窄寬比<0.5時，頻率會低於等高度但體積較大的圓柱。

Using experimental methods to analyze the acoustic effects of jet-excited Helmholtz resonators with different shapes.Making different resonators by paper tubes and pvc plastic tubes.
The experimental content is to observe the acoustic characteristics of several basic parameters of Helmholtz resonators,which includes length of neck,height of cylinder,diameter of cylinder,area of aperture,shape of aperture,position of aperture. Observing the acoustic characteristics of some Helmholtz resonators of special shapes,which includes the curved cylinder,the combination of inner and outer cylinder, the narrow-mouth bottle.
The results show that all basic parameters of Helmholtz resonators are roughly conformed with theorical equations except the shape of aperture and the area of aperture,which can cause some deviations because of the change of vibration mode. For the combinations of inner and outer cylinder, when the inner cylindr occupies volume smaller than 50% of outer cylinder, the frequency will decrease. For the curved cylinders, the frequency of the curved cylinders with sharper angle(90°) will decrease compared with the straight cylinders,and the curved cylinders with easer angle(135°) will increase compared with the straight cylinders. But the change of the frequency of the curved cylinders are within 10%. For the narrow-mouth bottle, when the ratio of narrower diameter to wider diameter is smaller than 0.5, the frequency will decrease compared with the cylinders with the same height and bigger volume.

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