shared mooring in FASTFarm

[cjwan12589]

Dear Professor jjonkman, I am trying to use the function of shared mooring in FASTFarm, and now I have encountered some problems. I hope you can give me some guidance, thank you very much!

1. Currently in FASTFarm, is the setting of shared mooring only applicable to the input file of MoorDyn v1 version? Is it available for MoorDyn v2 (latest version)?
2. For non-shared mooring lines, can they also be set at Farm level like shared mooring lines in .fstf file? Or does it need to be set in a.fst file?

[jjonkman]

Dear @cjwan12589,

Here are my responses:

1. The shared mooring functionality of FAST.Farm is supported by interfacing an instance of MoorDyn v2 at the farm (FAST.Farm glue code) level.
2. Non-shared mooring lines in FAST.Farm can be modeled either at the farm level or at the individual turbine (OpenFAST) level.

Best regards,

[cjwan12589]

Dear Professor jjonkman, Thank you for your answer, So is the output keyword of the shared mooring system based on moordyn-V1 or moordyn-V2? Or is it both?

[jjonkman]

Dear @cjwan12589,

If you are using FAST.Farm to model a floating offshore wind farm with a shared mooring system, MoorDyn v2 will be used (not MoorDyn v1). When MoorDyn v2 was introduced in OpenFAST and FAST.Farm, MoorDyn v1 was deprecated.

Best regards,

[cjwan12589]

Dear Professor jjonkman, Thank you very much for your answer, now I understand this point, but now I simulated the floating wind farm in FASTfarm, and I encountered the following error, I don't know why, can you give me some answers? Thank you very much!The following is also my .fstf main input file and python package out of the wind grid diagram. FASTFarm.txt

[jjonkman]

Dear @cjwan12589,

Which version of FAST.Farm are you running? Have you tried the newest release, v3.5.3?

Best regards

[cjwan12589]

Dear Professor jjonkman, I am using FASTFarm v3.5.2, is this a version problem? I personally think it seems to be a problem with the encrypted grid, perhaps the floating wind turbine is moved too far outside the scope of the encrypted grid, resulting in the inability to extract wind speed to calculate the aerodynamic load. Can you provide some ideas, thank you very much！

[jjonkman]

Dear @cjwan12589,

I'm not sure what you mean by "encrypted" grid, but I would first try upgrading to FAST.Farm v3.5.3.

I thought that large floater displacement my be the issue, but it appears that the error is triggered at time zero, which I would not expect would already have large floater motion, unless you are initializing the system with initial displacements?

Best regards,

[cjwan12589]

Dear jjonkman, I'm sorry I misstated it, In fact "encrypted" grid is a high-resolution grid, I tried to upgrade FAST.Farm to v3.5.3, and also tried to expand the range of high-resolution mesh, but there are still errors, as shown below, could you give me some guidance? It means a lot to me. Thank you very much!

[jjonkman]

Dear @cjwan12589,

Now it appears that the error is triggered 3 seconds into the simulation. My guess is the floating wind turbine is displacing enough that an aerodynamic analysis mode leaves its corresponding high-resolution domain.

Best regards,