Resonance of water in a sphere

[PH7SICS]

http://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe2.html

According to the above link the calculated speed of a wave in water is 1483m/s, whilst the measured speed of a wave in water was 1482m/s @ 20C

Imagine therefore we have a huge sphere with an internal diameter of 1482 meters and it is filled with water. At the centre of this sphere there is a point source of acoustic waves which occupies zero dimensions (its theoretical!). This point source emits an acoustic pulse the wave of which reaches the wall of the sphere in half a second and rebounds to reach the centre of the sphere in exactly one second.
If the point source was to be driven at one cycle per second or one Hertz resonance should therefore occur.

If my target resonant frequency was 42.8khz then it should be a matter of scaling i.e. 1482 / 42800 = 0.034626 meters or 34.62mm internal diameter.

obviously not sure about this so that is why I posted this here

 

[LightHero]

.Yes, this calculation should be correct. The speed of sound in water is governed by the medium through which the wave travels, and so scaling the internal diameter of the sphere to the desired frequency will produce the correct result. Keep in mind that the frequency of the wave produced by the point source must also match the desired frequency of the resonant frequency, or else the resonance may not occur.