FAST.Farm Mesh Mapping: Node 1 does not project onto any line2 element.

[lusoalman]

Hello dear community!
I want to do a simple steady FAST.Farm simulation with two wind turbine models with D=1.2 m. When I run FASTFarm v3.5.0 on my windows 10 I get this error for both turbines: Farm_Initialize:T1:Farm_InitFAST:FWrap_Init:MeshMapCreate:CreateLoadMap_L2_to_L2:CreateMapping_Pr jectToLine2:Node 1 does not project onto any line2 element. Closest distance is 0.12987 m.

According to previous issues in the community my nodal points from the .fstf the aerodyn and the elastodyn files are not matching. But I can't find the problem.

WTM_D1d2_Aerodyn_T1.txt .dat
WTM_D1d2_ElastoDyn_T1.txt .dat
WTM_D1d2_2T5D.txt Main Input .fstf
WTM_D1d2_T1_6mps.txt Turbine Input .fst

Thank you so much for any help!
All the best,
Sara

[jjonkman]

Dear @lusoalman,

Actually, the CreateLoadMap_L2_to_L2 error is regarding the mesh-mapping search in the OpenFAST wrapper within FAST.Farm, which is the mesh-mapping search between the AeroDyn Line2 blade load output mesh and the radial finite-difference grid that is stored on a mesh in the OpenFAST wrapper. I would guess the issue is in your AeroDyn blade input file, WTM_D1d2_Aerodyn_Blade.dat, which you have not shared. A similar question was asked and answered in the following issue: #1044.

Best regards,

[lusoalman]

Thank you for the quick answer!
Here is the missing file:
WTM_D1d2_Aerodyn_Blade.txt
What is the AeroDyn Line2?

[jjonkman]

Dear @lusoalman,

I don't see any issues with your AeroDyn blade input file. I'm not sure I understand what the problem is, especially considering the rather large distance reported (0.12987 m) relative to the size of your radial discretization (0.0167). I would suggest stepping through with the debugger to identify the issue.

I do see that your polar grid in FAST.Farm has quite a fine resolution relative to your chord (dr << c_max) and that the radius of your polar grid is not large relative to the rotor radius, which may be problematic once you can get FAST.Farm to run, but I would not expect these issues to trigger the error you are receiving. Regardless, though, I would suggest following the FAST.Farm modeling guidance (https://openfast.readthedocs.io/en/dev/source/user/fast.farm/ModelGuidance.html) when setting up spatial-temporal discretizations of FAST.Farm. If you are not already aware, there have been quite a few improvements recently to the python scripts that support FAST.Farm, which follow the modeling guidance, see: OpenFAST/python-toolbox#56.

Best regards,

[lusoalman]

Thank you again for the help and the tip! I will look into it and check everything again step by step.

All the best,
Sara