I am using FASTv8 through your MATLAB Framework. Recently, I converted FASTv7 Input files to FASTv8 using the MATLAB script provided but once I start the simulation, I get this error:

The simulation environment works fine with the NREL5MW turbine.
Do you have any idea what triggers the runtime error?


My guess is that the controller you are using (or some other part of the code that didn’t come from NREL) is trying to read from a file named ‘U:\git\VAero\windturbineframework_mreich\fort.86’, which doesn’t exist.

I get a similar error when running openFAST and when SubDyn are calculating the internal modal eigenvectors. The error code is:

Do anyone know why I get this error and also how I can fix it? Any tips is appreciated.


Dear Daniel,

Which version of OpenFAST are you running? Did you change the source and/or compile yourself? Are you running model provided by NREL or one you developed yourself?

Best regards,

Dear Jason,
I am running the last version of OpenFAST which I downloaded and compiled on friday. I have managed to come around this error by setting the value of in the subdyn-file for number of divisions equal to 1 and not 2 as the value in the test files from NREL are. Does this do anything with the calculation or is this ok?

Thanks for the help.

Dear Daniel,

Are you running the OpenFAST model of the NREL 5-MW turbine atop the OC4 jacket found here: … rr_MGrowth? If I understand correctly, this model runs for you fine with with NDiv = 1, but not 2; is that correct? Do other simulations from the r-test fail when running with the version of OpenFAST you compiled?

Input parameter NDiv in SubDyn determines the number of beam finite elements each member is discretized into. For all members are short, setting NDiv = 1 may be OK. If the members are long or if you want to output loads within the member (not just at the member ends), setting NDiv > 1 is important.

Best regards,

I am running the OpenFAST model of the NREL 5-MW on top of INNWIND jacket found on this forum. All the r-test ran fine and all tests were given past as a grade.

Thank you for information about NDiv. I think NDiv=1 is fine for what I am doing at this point.