CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   FLUENT (http://www.cfd-online.com/Forums/fluent/)
-   -   Vertical Axis Turbine Simulation (http://www.cfd-online.com/Forums/fluent/121238-vertical-axis-turbine-simulation.html)

dalecooper July 24, 2013 06:51

Vertical Axis Turbine Simulation
 
Hello,

I have been doing some simulations with vertical axis turbines in Fluent. In order to achieve good results I have tried using the Inflation option in Ansys Meshing module around the different airfoils in the turbine. But I found a problem in Fluent that says: 'Divergence detected in AMG solver'. When I disable the Inflation option the problem disappears.

I have tried different meshing methods as quadrilaterals and triangles as well as refining the mesh using sphere of influence around every airfoil, but still I haven't found a proper solution to the divergence error.

Thanks in advance and best regards.

vasava July 24, 2013 07:42

Are you working with dynamic mesh or moving frame of reference?

dalecooper July 24, 2013 07:57

Quote:

Originally Posted by vasava (Post 441680)
Are you working with dynamic mesh or moving frame of reference?


I'm working with sliding mesh techique. I have defined two interfaces to separate the rotating airfoils zone and the non moving mesh zones of my domain.

I have obtained some good results with the quad mesh, but when I use the triangle mesh the results are completely different and the computational time increases too much.

vasava July 24, 2013 08:53

The divergence message is because the pressure distribution is not correctly predicted.

You can check the pressure distribution and check if there is abnormal pressure distribution in some region. You can improve or refine mesh in that region.

If the pressure distribution is ok then you can lower the under relaxation factor for few iterations until the pressure is back to normal.


All times are GMT -4. The time now is 08:35.