Hydro acoustics

[Kris01]

I am performing a study on the resonance of thin round plates in a fluid (water). However, I can not find any information about the resonance of plates in a fluid.

How can I calculate the resonant frequency of a plate in water if I know the resonant frequency in air?

Thanks!

 

[MotorVib]

The water should no effect the freq.

Chris

"In this house, we obey the laws of thermodynamics." Homer Simpson

 

[GregLocock]

Well, yes and no. Fluid mass loading is a well studied effect. I /think/ it is mentioned in Harris' Vibration Handbook.



Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[pja]

Look for a book by Blevins for such solutions

 

[MotorVib]

The fuild should only act as a damper and that has little effect on freq.

Chris

"In this house, we obey the laws of thermodynamics." Homer Simpson

 

[GregLocock]

Not necessarily.

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[rob768]

It has a very large effect, lowering the natural frequencies and indeed, as mentioned, Blevins gives the proper formulas for the added mass

 

[cbrn]

Hi,
on this point what I can say is restricted by my employer, but I can say that:
- MotorVib is substancially wrong
- GregLocock is right
- Pja and Rob768 are right and point you in the right direction.

Regards

 

[tomirvine]

I have posted a tutorial with some very basic information on the "added mass effect" at:

http://www.vibrationdata.com/tutorials2/added_mass_fluid.pdf

Tom Irvine

http://www.vibrationdata.com