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-   -   Von-Karman Vortex shedding (https://www.cfd-online.com/Forums/cfx/218534-von-karman-vortex-shedding.html)

sarbakhshian June 24, 2019 08:45

Von-Karman Vortex shedding
 
2 Attachment(s)
Hello
I'm trying to simulate FSI example proposed by Turek-Hron in which flow over a cylinder causes vortex shedding behind the cylinder. When I simulate this example using just CFD simulation (not FSI) with the velocity profile given in the article, I can see vortex shedding behind the cylinder. But whenever I add a beam shape structure behind the cylinder to run with the two way FSI approach, nothing happens behind the cylinder and I can not see Von-Karman effect.
Does any one have any idea what should i change in my simulation.
I'm attaching two pictures of my both simulations.

evcelica June 24, 2019 13:52

Wouldn't the tail reduce/stop vortex shedding?

Also it looks like you have walls in the model with the tail on the top and bottom, but not in the one with just a cylinder? These walls could reduce vortex shedding as well, and should be moved further away.

sarbakhshian June 25, 2019 02:49

Quote:

Originally Posted by evcelica (Post 737121)
Wouldn't the tail reduce/stop vortex shedding?

Also it looks like you have walls in the model with the tail on the top and bottom, but not in the one with just a cylinder? These walls could reduce vortex shedding as well, and should be moved further away.

thanks for the reply dear Erik. I'm sharing a youtube link here for you to see what i'm trying to deal with. the geometry must have a tail and i need it's time history x&y displacement for verification
https://youtu.be/15VOBaQ2oJY

ghorrocks June 25, 2019 07:14

You never said the tail was flexible. This is a challenging simulation and you can expect to need to do some careful work before it is completed. I would recommend you do a static Von Karman vortex simulation and check you can successfully model the vortex on a station before starting FSI.

When you add the FSI component start off with the tail quite mechanically stiff so it does not flex much. Once that is working then reduce the stiffness to the correct amount.


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