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-   -   Rotating problem / transient / 2D (http://www.cfd-online.com/Forums/cfx/88885-rotating-problem-transient-2d.html)

Logan86 May 29, 2011 09:50

Rotating problem / transient / 2D
 
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Hi
I have to simulate a special vertical wind turbine where the airfoils itself are rotating. It should look like this http://www.youtube.com/watch?v=U9d0F...eature=related , but with rotating airfoils.
I have done all the tutorials, and read old threads here, so simulating a normal vwt is no problem, but my case is quite tricky because of the rotating domain in a rotating domain.
How should I make this?
(especially the problem of the non stationary rotation axis of the airfoil)

Setup details:
2D
Transient Rotor Stator Interfaces between the three domains

ghorrocks May 29, 2011 19:04

You can do the simply rotating domain with a rotating frame of reference. But the domain with the rotation within a rotation will not work with this approach. You will need to use a moving mesh approach to do this and define the motion.

baserinia May 29, 2011 22:01

There might be a tricky workaround for this problem, but I have never tried it. You can assume your turbine is fixed, but the outer domain rotating. Therefore, you'll have a rotating domain on the outside and another rotating domain around the airfoil.

The problem is that the turbine is actually rotating wrt an inertial reference frame. Therefore you have to add the non-inertial forces (centrifugal and Coriolis) as source terms into the momentum equation.

ghorrocks May 30, 2011 06:14

Nice idea, providing the non-inertial forces are small this approach would work. It would make post-processing a bit of a challenge.

But if the non-inertial terms are significant then you have no choice but to model the real motion, and I cannot see any other way except moving mesh for the inner domain.

Logan86 May 30, 2011 10:39

Thanks for your help. I also think that a moving mesh could be the solution for my problem, but in my first attempts the airfoil got deformed while moving, so the solution was useless.

bramdiff July 8, 2011 04:56

Hi,

I have setup a similar problem, you might find this thread helpful...

http://www.cfd-online.com/Forums/cfx...g-domains.html

James

Logan86 July 8, 2011 06:57

Thanks a lot James!!
I will try it immediately!


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