作者NewFreedom (反社會)
看板Physics
標題Re: [轉錄]Re: [問題] 請問聲波在開口管為何會反射？
時間Fri Jul 3 23:10:43 2009
我把原文書的解釋打上來好了
Sound is a pressure wave, and a compression region of the sound wave is
constrained by the sides of the pipe as long as the region is inside the pipe.
As the compression region exits at the open end of the pipe, the constraint of
the pipe is removed and the compressed air is free to expand into the
atmosphere. Thus, there is a change in the "character" of the medium between
the inside of the pipe and the outside even though there is no change in the
"material" of the medium. This change in character is sufficient to allow
some reflection.
大意就是管內的密部會被管壁所拘束,管外不會,雖然管內外是相同的空氣,
但因前述環境的不同,可造成反射.
至於此現象的詳細參數,是壓力or聲速不同等等,我就不會了,請會的人解答指正 ^^
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1F：推 alenbe:感謝提供教科書的說法，上一篇提到的補償性波，我也不懂 :P 07/03 23:20
2F：推 denisck123:所以基本上就跟我上篇說的是類似的 07/04 00:05
3F：→ denisck123:管口內疏密波碰到管口外時可看成細繩跟粗繩的想法 07/04 00:07
4F：→ denisck123:也就像是介質(環境)不同一般 所以會有反射跟透射囉 07/04 00:07