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SWRT tests cases with tail fin do not match FAST7 results #128

Closed andrew-platt closed 2 weeks ago

andrew-platt commented 2 months ago

The SWRT cases now include a new tail fin model that theoretically is similar to the FAST7 cases (see PR #126).

Comparing the results for the cases with FAST7 shows some notable differences. There have been significant improvements to the AeroDyn that may account for the differences. Someone should double check this though.

Screenshot 2024-06-29 at 8 35 30 AM Example from the SWRT_YFree_VS_EDC01 case (Test16.out from the FAST7 CertTest). Note that SubAxInd has been turned off in the FAST7 run since TFinIndMod=1 is not available in the current dev branch of OpenFAST (3d476c595).

@abhineet-gupta may have some insights here.

abhineet-gupta commented 1 month ago

I did some digging and reduced the problem to a very simple case of steady wind, all flexible and turbine degrees of freedom switched off; but I still couldn't match the tail fin forces. OpenFAST gives expected results but Fast V7 does not.

Compare.pdf

Not sure what's going on with Fast V7 here (or am I missing something) but will look into it and discuss it with @jjonkman if I can't find a solution.

andrew-platt commented 2 weeks ago

After further discussion, we concluded that FAST7 is incorrect. Since we are not going to update FAST7, we are considering this as solved and will close the issue.