Anti-vortex wind strake functionality 2

[atrizzy]

A client is asking me if they can safely insulate an unlined steel stack and associated helical wind strakes.
A look at STS-1 indicates fairly strict sizing requirements for strake length, and if they add the insulation, this will decrease the projection of the strakes form the side of the stack.

On one hand, I don't see any justification in the code for allowing this. On the other, there will still be a vortex shedding element, just not quite as protrusive as prescribed.

The client wants to do this as they think it will reduce corrosion inside the stack.

Would you permit this? I'm leaning towards telling them that they're on their own with this. Structural engineer here with no knowledge of the basics of vortex shedding analysis.

 

[phamENG]

Structural engineer here with no knowledge of the basics of vortex shedding analysis.

I got into it a few years ago, but only because I was on staff at the plant where the question came up. Now, as a consultant, I would refer such requests to another engineer or get another consultant to talk to as a specialist (if it's a frequent client). I just don't know enough about it to give good advice.

 

[EdStainless]

They need to hire someone to run a fluid dynamics model on it. I wouldn't have anything to do with it.

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P.E. Metallurgy, consulting work welcomed

 

[dvd]

These folks did some design work for me several years ago and made a favorable impression -

https://www.mecaenterprises.com/engineering/

 

[JLNJ]

Here's their page on helical strakes. Helpful, but not exactly definitive.

https://www.mecaenterprises.com/getting-twisted-about-helical-strakes/