# Stationary waves

1. Mar 3, 2010

### FizixFreak

hi there i just wanted to know that how are waves reflected in an open air column and what do we mean about odd harmonics? thank you

2. Mar 3, 2010

### tiny-tim

Welcome to PF!

Hi FizixFreak! Welcome to PF!
See the PF Library on open end

3. Mar 6, 2010

### FizixFreak

THE website great man thank you very much

4. Mar 6, 2010

5. Mar 6, 2010

### Staff: Mentor

Odd harmonics are odd-integer multiples of the fundamental frequency: $f_0$, $3f_0$, $5f_0$, $7f_0$,etc.

6. Mar 7, 2010

### FizixFreak

i know that but why only odd harmonics are produced in an closed end column?????

7. Mar 9, 2010

### FizixFreak

no replies
i hope i m not wasting your time but i really need to know this stuff

8. Mar 9, 2010

### Stonebridge

Because the closed end must be a node and the open end an antinode. This means that only 1/4 or 3/4 or 5/4 or 7/4 etc of a wave can fit in the tube. This gives only odd harmonics.

9. Mar 9, 2010

### Staff: Mentor

See the following page:

http://cnx.org/content/m12589/latest/

Scroll down to the diagram labeled "Allowed Wavelengths in a Stopped Tube."

How do the second, third and fourth waves compare in wavelength to the first one? (How much longer are they?)

Notice that in the first one (the fundamental), you're seeing only 1/4 of a wavelength.