Optimizing Organ Pipe Modes with Vent Holes

[mtreichl]

Homework Statement

Where would you locate a small vent hole to encourage the third mode of an open pipe? The fourth mode?

Homework Equations

Hint: Where is a node of the desired mode?

The Attempt at a Solution

Does this mean 1/3 of the way down for mode 3 and 1/4 of the way down for mode 4?

 

[Spinnor]

See the following picture of both open and closed organ pipes,

http://www.daviddarling.info/images/nodes_and_antinodes.jpg

From,

http://www.daviddarling.info/encyclopedia/H/harmonics.html

From the first picture it looks as though you would have holes at the position of the anti-node?