coolparticle

Hello everyone, I have been doing some research about Helmholtz resonance of a bottle for a science competition, but I don't find it clear how the Helmholtz frequency in a bottle is connected with a concept of seeing a bottle as a closed tube of a length L and fundamental frequency f=v/4L ? I understand that the latter formula does not consider the shape of the bottle, while Helmholtz resonance does. When we pour liquid in the bottle and observe the change in resonant Helmholtz frequency with change in volume, we see that shape matters (I guess because if affects the amount of volume of air in the "resonator"). Still, if the bottle looked like an almost perfect cylinder and we poured water in it to observe change in frequency, would Helmholtz frequency (recorded and determined by computer) and f=v/4L (where L is the height of air column) give the same values? Please, help me, I'm lost Thanks!