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| 題 名 | 漫散入射狹縫之音響穿透研究 |
|---|---|
| 作 者 | 陳國在; | 書刊名 | 中華民國音響學刊 |
| 卷 期 | 2:1 1993.11[民82.11] |
| 頁 次 | 頁42-54 |
| 分類號 | 334.5 |
| 關鍵詞 | 漫散入射; 狹縫; 音響穿透; 穿透損失; Randomly incident; Aperture; Acoustic transmission; Transmission loss; |
| 語 文 | 中文(Chinese) |
| 中文摘要 | 本文利用理論數值解析配合實驗室測定方法,探討聲音漫散入射狹縫之音響穿透 。為確定僅考慮零階模態解(modal solution of zero order)之三維平面波理論,狹縫於 較低頻率之非完全音響穿透情況,是否仍具適用性,本文首先完成迴響音場入射狹縫之穿 透損失測定。另外,為簡化繁瑣之數值計算,文中亦對狹縫之聲音入射口處,假設為低頻 率對應入射之音響完全反射。 本文已完成0.78,1.5與6.6cm等三種開口尺寸狹縫之穿透損失於較底頻率之理論數值計算 與全頻率域之實驗室測定,以上述二者之結果比較,對上述三種尺寸狹縫之穿透損失測定結 果,顯示大於1250 Hz之入射聲音,均造成三種狹縫之音響完全穿透。另外,對低於1250 Hz 之入射聲波,三種狹縫之穿透損失數值計算與實驗測定結果,對應頻率之變化趨勢,甚為吻 合;其低於630 Hz之數值差異,除於甚低頻率之較大量測誤差造成異常外,均小於四分貝。 |
| 英文摘要 | This paper presents both the theoretical and experimental studies on the randomly incident sound transmission through apertures. In order to make sure if the three dimensional theory in which only plane-mode solution was taken is accurately applied to the problem for sound transmitting through apertures at low frequencies, the laboratory measurement on acoustic transmission loss for reverberantly incident sound transmitting through aperture was worked out first Moreover, in order to simplify the complicately numerical calculation in the theory, the assumption of perfect reflection on the entrance's surface of aperture in the reverberation room was also edone. Both the theoretical calculation at low frequency and laboratory measurement for full frequency range on transmission loss of apertures having three various depths of 0.78, 1.5 and 6.6 centimmeters when randomly incident sound waves were transmitting through them, including the comparison between above two results, all had been worked out in this paper. The trend of measured transmission loss versus frequency ranging from 100 to 5000 Hz for above three apertures shows that perfect acoustic transmission (i.e. almost zero sound transmissio loss) will reach when the frequency of incident sound is beyond 1250 Hz. Otherwise, the fact that the trend of calculated transmission loss versus frequency for frequency of the incident waves being lower than 1250 Hz coincides well with those of the measured. And the numerical difference between them always lies within four decibels for frequency being less than 630 Hz except an abnormality resulting from the measured errors at very low frequency in which the acoustic field of reverberation room doesn't uniformly distributed. |
本系統中英文摘要資訊取自各篇刊載內容。