Learning Forum

[Yerucham100]

I am performing a CFD simulation on a wind turbine blade, I noticed that I get better results when I remove the inflafion layer but this makes little sense to me. Why is the inflation layer negatively affecting my results?

[peteroznewman]

How do you quantify the quality of the results?

Please show the mesh metric of skewness for the mesh with and without the inflation layer.

[Yerucham100]

By quality I mean that the torque calculated is closer to the actual value but now that you mention it, the skewness improves when I remove the inflation layer but the improvement is very small in my opinion compared to the torque

[Keyur Kanade]

what viscous model you are using?

ke ewt and kw sst will require inflation layer. 

[Yerucham100]

I am using kw sst viscous model

[Keyur Kanade]

kw sst will require inflation layer. 

what is mesh orthogonal quality?

min orthogonal quality should be more than 0.1. 

https://www.youtube.com/watch?v=AzvPxjNyr3w

 

[Yerucham100]

The minimum orthogonal quality is about 0.03

[Rob]

 With mesh quality down there I suspect it's more the case that the non-inflated model is less skew and so you're seeing a better result. Ie it's not the lack of inflation that's helping, more the reduction in poor cell quality. 

[Yerucham100]

That could be it, but I now think the correct results I was getting before were pure coincidence because on reducingthe tip speed ratio of the blade from 7 to 5, the torque doesn't go down as expected, the error is significant but when I restore the inflation layer, the torque decreases with tip speed ratio as it should. I think I need further mesh refinement with the inflation layer to get good results

[Keyur Kanade]

if this helps you, please mark this as 'is solution' to help others on forum.