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What kind of shape has the lowest flutter wind speed and is the most unstable?

I mean for rigid body.


Yes, I know many factors affect the flutter in a MSD system (for rigid body), however I'd really want to know what is the worst case one could have? No matter what mass damper or spring one use... (I am not from the ame, Im a civil engineer)

The reason I asked this is, I want to use CFD to reproduce the phenomena, and as you may know CFD is very sensitive to the Reynolds number, so I'd like to know what is the lowest Reynolds number case that can have a clear flutter instability phenomenon.

Thanks a lot.

Sorry, my bad, forget about the questions.

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Flutter is not a question of shape alone. You have to be more specific. –  Georg Sep 20 '11 at 16:33
OK, look at this page: de.wikipedia.org/wiki/Wirbeldurchflussmesser I think this construction shows, that flutter is more a question of sharp edges than general shape. If one assumes a rigid body, a kind of thin blade perpendicular to flow would be the best thing. For real bodys that triangle is best, to have stability to forces parallel to flow. –  Georg Sep 20 '11 at 17:17
You can cause flutter at lower reynolds numbers by blocking some of the air before it reaches the body. For example, suppose you have a horizontal cylinder used as a hinge ahead of a long, rectangular strip that runs perpendicular to the air flow. If the diameter of the cylinder is increased to be thicker than the strip, then the strip is more likely to flutter. –  xpda Sep 20 '11 at 19:05
Are you talking about the vortex shedding, the stronger vortex sheds, the sooner flutter happens?? –  Daniel Sep 20 '11 at 19:35
+1 great soft-question –  Argus May 31 '12 at 3:21
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