Step in Calculating Flow Induced Vibration

[bmoc]

I have water flowing through vertical bars with a defined unsupported length. How do I prevent resonant vibrations induced by flow not less than 2.5 times the vortex shedding velocity? In other words, what range must the frequency be within to insure that I won't have resonant vibration of the bars?

Is Strouhal number 0.20 for this application?

 

[hacksaw]

what flow velocities are you dealing with?

 

[bmoc]

Velocity is 1.5 fps or less.

 

[hacksaw]

calculate the drag load, use that as a basis for design, as a starting point. you can always apply a design factor.

vortex shedding at that velocity, inless you are dealing with pilings is generally a secondary issue. what you'll have is a form of self-excited oscillation rather than mechanical resonance.

if you have the tools for developing the critical frequencies of your structure while it is in the fluid, you can do that and then make some judgement about the relative significance about the intensity of the FIV.