Fixed pitch, variable speed stall turbine in WISDEM

Hi everyone,

I am trying to build a model in WISDEM of a turbine with fixed pitch and variable speed with stall power control. I have started with the ‘03_blade’ example and made the following changes:

Geometry file:
max_pitch: 0

fix_pitch_regI12: true
max_pitch_perf_surfaces: 0.0
min_pitch_perf_surfaces: 0.0
n_U_perf_surfaces: 20
n_pitch_perf_surfaces: 1

I loaded the files into the GUI and ran the ‘no_opt’ and ‘aero’ analyses. However when I use the compare_designs script (loading the .pkl files) the plots still show that pitch regulation is active. This is also clear from the ‘rotorse.rp.powercurve.pitch’ entry in the ‘blade_out.xlsx’ file, which also shows that the pitch does not remain at 0.0 in Region 3.

Could you advise on how you would approach this problem, and where I may be going wrong? My goal is eventually to run an aero-structural blade design optimization for this turbine. Thank you.

Best Regards,

Drew Gertz
Northwind Engineering OÜ
+372 5565 0147

Hello Drew,
WISDEM does not implement a stall-control logic. You’ll need to work on the source code to achieve that.
This said, it should not be a major effort.

You’ll need to work within the explicit component ComputePowerCurve …
and you’ll need to bypass the steps where the pitch is controlled, such as here …
and here …

I hope this helps.
Best regards,
Pietro Bortolotti

Hi Pietro,

Thank you for your quick reply. I have now modified the code to use the modeling options max_pitch_perf_surfaces and min_pitch_perf_surfaces as the bounds in the pitch search functions. I also added a clause in Region 3 that checks max_pitch_perf_surfaces. If it is >0 then as usual it solves for the Region 3 pitch. Otherwise it solves for the Region 3 rotor speed. I ran example 03_blade (no opt) for both cases and you can see the results below. It should be sufficient for my purposes. Thanks for your help.




Best Regards,

Drew Gertz
Northwind Engineering OÜ
+372 5565 0147