water resonance in a sphere

[Hydro-Cell]

i am trying to find the answer to a question which i hope someone here can help with

i have 3 stainless steel spheres, diameters of 15,20,and 32cm

if i were to fill them with water what would the resonant frequency of the sphere be???
i need to know so that i know exactly what frequency to hit them with.

this is for ultrasonic cavitation project.

upto now i have been using 42khz which has proved effective, but i would like to try with a resonant frequency for better results.

a formula would be good if there is one.

last part is what size sphere would be needed for 42khz resonant frequency???

[ramset]

 User E M devices is a genius antenna man
I also know he has interest in this project He is a great member and has always answered my PM's

Also if you can't wait on the piezotransducer info user Tinsel Koala made some suggestions on this topic[achieving resonance in a fluid]] he MAY have a source for the piezo transducers
   Chet

[gyulasun]

Hi,

Perhaps this paper even if not on all your questions but may give some hints, or the References at its ends:

http://www.wooster.edu/physics/jrIS/Files/Patton_web_article.pdf

I found this by some search, I am not an expert on this unfortunately.

rgds, Gyula

[Pirate88179]

OK, this is from a guy that really does not know what he is talking about, but, here goes.  the resonant frequency of the empty sphere is easy to determine.  Filling it with water, which has a dampening effect, will change that, to a lower frequency.  Someone else on another topic suggested to hit the item in question with a frequency generator.  By doing this, you can determine at least one resonant frequency even though there will be several and also , harmonics of these frequencies.

It is kind of like tuning a guitar or a piano.  The sphere (filled with water) will "ring" at a resonant freq.  I don't know how to explain this in more detail and this info may not be very helpful.  This might get you started tho.

Bill

[Hydro-Cell]

hi
i know that when an object hits resonance it will "ring", but what i dont know is how to find it with a formula. i can do it with trial and error for instance, by setting the ultrasonics away at a known frequency and scan through the frequency until it starts to feed back into the oscilloscope, there will be a peak when this happens. this is resonance.
the reason i would like a formula is so that i can try different size spheres and instead of scanning each one by trial and error i would like to be in the range needed..

i would like to operate the ultrasonics in or around the 40 khz ish mark so it may involve using a harmonic with the bigger spheres