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sasasa April 12, 2014 10:08

Simulation of Vertical axis wind turbine
 
1 Attachment(s)
I have designed and meshed a VAWT in Gambit,with different mesh zones as shown in the attached figure.The ring has to rotate as moving mesh at 3 r/s.
What are the settings required for it?Dynamic mesh-negative volume error appears when calculating. What is the udf required?

Far April 12, 2014 16:18

You can do it with the help of sliding mesh and frozen rotor model.

sasasa April 13, 2014 02:42

VAWT simulation
 
I need to make the ring rotate(moving mesh). Interfaces are defined.What is the setting/udf ?

Far April 13, 2014 06:28

you should go for sliding mesh. You will see the ring is moving. Results with dynamic mesh and sliding mesh will be same.

sasasa April 13, 2014 11:01

I tried mrf model.It produces divergence with many settings..The inner ring has to rotate.Could you list the settings.The ring is defined as a separate zone

CFD-fellow April 14, 2014 04:55

Quote:

Originally Posted by sasasa (Post 485822)
I tried mrf model.It produces divergence with many settings..The inner ring has to rotate.Could you list the settings.The ring is defined as a separate zone

Hi
for simulating sliding mesh (which is a sub branch of dynamic mesh, but the difference is that the cells move rigidly without any geometrical change), you should provide two interfaces locating on each other, one belong to rotating zone and the other to stationary one.Then the following procedure lead you to correct answer:
1-change the solver to unsteady
2-change the ring zone from stationary to sliding mesh
3-couple the two interfaces from define>grid interface
3-choose a time step so that the ring rotates 1 degree
4-then about 30 iteration per time step is enough in your case i think
Best regards

sasasa April 14, 2014 07:18

1 Attachment(s)
The outer circle is 1 interface.The inner circle is 1 interface.The ring between the 2 contains a separate mesh which has rotate at 3 r/s.The remaining mesh is separate and stationary.There are only 2 concentric interfaces and 2 cell zones.Where is sliding mesh option under dynamic mesh(fluent 12)picture is attached

mct90 April 17, 2014 08:03

Hi,
How did you define outer circle's diameter? And the outer domain? Is there any reference for them?


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