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一个老兵

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Post By：2008-7-10 12:00:38 [显示全部帖子]

k=2π/λ

λ is the wavelenth of the sound.

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Post By：2008-7-10 16:53:20 [显示全部帖子]

以下是引用digital在2008-07-10 15:52:11的发言：

老兵: so I guess that this derivation is based on "惠更斯原理", right?

Yes,that is right.

In acoustics, with the wavelenth>>lenth of object, sound is following the "惠更斯原理".
In fact, there is so called piston radiation in the theory.
Some of friends here studied the related theory in the university.
The textbook is a very famous one which is <Fundemental of Acoustics>, but it is in Chinese.
There are some books in English. For instance,

Sound System Engineering (Hardcover)
by Don Davis (Author), Eugene Patronis (Author) is a good book, I think.
Patronis wrote a lot about the sound radiation.

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Post By：2008-7-10 16:54:42 [显示全部帖子]

以下是引用digital在2008-07-10 15:40:08的发言：

Thank you very much! That slide is so succinct that many details are omitted.

So k=2π/λ=2πf/c=w/c,
and kr12=2π(r12/λ) must be the phase difference between those two area elements, and (r12/λ) must be the wave number, I guess.
In that sense, kr12=2π(r12/λ)=2πf(r12/c)=2πf delta_t12 = w delta_t12
That makes sense!

老兵Thank you so much!

k=2π/λ=2πf/c=w/c,

Yes,
thank you,"digital".

[此贴子已经被作者于2008-07-10 16:58:04编辑过]