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-   -   Vortex Shedding by CFDesign (http://www.cfd-online.com/Forums/main/80775-vortex-shedding-cfdesign.html)

Joke October 6, 2010 06:11

Vortex Shedding by CFDesign
 
Hi, Everyone
I'm joke. I am the newbie of this CFD filed.
I'm trying to learn both in univesity and myself to improve my CFD skill.
I tried to simulate vortex shedding by CFDesign.
I set up transient model, reynold no=1000, time step size=0.01, turbulence model k-epsilon with default other parameters setting(turbulence intensity 5%, Turb/Lam ratio 100, Cmu=0.09,etc).
I ran up to 4000 time step with 10 sub iteration.
But I still havn't got any vortex(you could see image below).
I tried to simulate this condition
the other CFD software such flowork, I got vortex easily.
So Could any guild me what I'm done wrong and what should I do?

Thank for advance
Best regard
Joke
http://img97.imageshack.us/img97/387...xsheddingf.jpg

nuimlabib October 12, 2010 21:16

actually if u use transient u can find the vortex shedding phenomena. by monitoring per time step or flow time. if u waited until you simulation finished, of course u couldn't find the vortex shedding because after sometimes the flow will be steady. i suggest u to use fluent and u can see the vortex shedding occurred at how many time after starting simulation.

lukemihelcic October 18, 2010 11:30

Vortex shedding..
 
Joke,
I set up a very similar simulation and was able to capture vortex shedding. The only thing I changes was the sub iteration, the default is 10, I switched to 3. I also saved at certain interval to animate the simulation. You also want to add slip condition to the top and bottom wall, you will also need a pretty dense mesh. If you have any additional questions the guys at support@cfdesign.com should be able to take a look at your set and give some additional advise. let me know how it goes...

-luke


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