Resonant frequency of a pipe submerged under water

[supak111]

How do I calculate a resonate frequency of a length of pipe submerged totally under water?

Do I just take speed of sound in water which is 1,481m/s at room temp, and decided it by length of pipe in meters multiplied by 4?

so at 20 celsius water and 20cm pipe it would just be: 1481 / (.2 x 4) = 1851.25Hz??

 

[Arjan82]

Something like that indeed: https://en.wikipedia.org/wiki/Acoustic_resonance

what makes you doubt?

 

[tech99]

How do I calculate a resonate frequency of a length of pipe submerged totally under water?

Do I just take speed of sound in water which is 1,481m/s at room temp, and decided it by length of pipe in meters multiplied by 4?

so at 20 celsius water and 20cm pipe it would just be: 1481 / (.2 x 4) = 1851.25Hz??

Remember that if the pipe is open at both ends then it needs to be half a wavelength long rather than a quarter.

 

[Arjan82]

The formula given is for a half open pipe

 

[supak111]

Thanks everyone, yes I was wondering about a pipe that's closed on one end, forgot to specify.

 

[sophiecentaur]

If the 'experiment' relates to some system for the measurement of pipe length then it may not be as simple as that.
On a practical level, the behaviour of a pipe full of water might be more affected by the material of the pipe than the air column that the model . The modulus of water is very high, compared with air so I wonder what the effective length of a PVC pipe might be. The pipe with water in it is likely to flex due to internal pressure variations and interact much more than for an air column in the same pipe (that's in addition to the different inherent wave speed).