i simply don't get fundamental harmonics. I understand the equations when you have a closed pipe or closed pipe one end and open on another -- but i just don't get the concept basically. What are the fundamental harmonics...etc. any help is greatly appreciated. Thanks!!
If you have standing waves (such as in a pipe, or say an electron in a potential well) then there are a discrete number of waves that will fit with an integer number of wavelengths.
I haven't taken basic physics in awhile, but in a closed pipe, I believe both ends must end at a node. In other words, they're fixed. If L is the length of the pipe, then the harmonics will have wavelength L, L/2, L/4, etc.