Reference models

The model that opens when using the default onshore template is the well known NREL 5-MW wind turbine. This section shows how to modify the default template to obtain two other widely used reference wind turbines, the DTU 10-MW wind turbine and the IEA 15-MW wind turbine
You can find

Note: several definitions of the blades can be found (for example blades made in order software). These definitions are supposed to be equivalent, but small discrepancies can occur. To ensure that our blade definitions are correct, we run verification tests that you can find in the Benchmarking tests. The detailed definition of the blades in Ashes is also provided in the DTU 10-MW and IEA 15-MW documents. 

The parameters that need to be modified to go from the NREL 5-MW turbine to the DTU 10-MW turbine are given in the following table:

PartParameterNREL 5-MWDTU 10-MWIEA 15-MW
Wind turbine Controller path-\DLL Controllers\BasicDTUController\BasicDTUController.dll\DLL Controllers\ROSCO\ROSCO.dll
Wind turbine 
Input file argument--IEA15MW.IN
Wind turbine->RNA Generator Variable speedBladed DLLBladed DLL
Wind turbine->RNA TransmissionGearedGearedDirect drive
Wind turbine->RNA Demanded pitch 
PIDBladed DLLBladed DLL
Wind turbine->RNA Tilt angle556
Wind turbine->RNA->Rotor BladeNREL 5-MWDTU 10-MWIEA 15-MW
Wind turbine->RNA->Rotor Cone angle2.52.54
Wind turbine->RNA->Rotor->Hub Radius1.5 m2.8 m3.97 m
Wind turbine->RNA->Rotor->Hub MassFrom radius105 520 kg190 000 kg
Wind turbine->RNA->Main shaft Hori. distance to hub5 m7.1 m10.604 m
Wind turbine->RNA->Main shaft Vert. distance to hub2.4 m2.75 m5.462 m
Wind turbine->RNA->Main shaft Shaft radius0.8 m1 m1 m
Wind turbine->RNA->Main shaft Wall thickness0.028 m0.049 m0.1 m
Wind turbine->RNA->Nacelle frame Mass240 000 kg446 036 kg630 888 kg
Wind turbine->RNA->Nacelle frame CM horizontal offset-1.9 m-2.687 m3.945 m
Wind turbine->RNA->Nacelle frame CM vertical offset1.75 m2.45 m3.352 m
Wind turbine->RNA->Gearbox Gear ratio9750N/A
Wind turbine->RNA->Generator Efficiency factor0.9440.9440.9655
Support structure->Tubular tower Height87.6 m115.63 mfrom file
Support structure->Tubular tower Top diameter3.87 m5.5 mfrom file
Support structure->Tubular tower Top thickness0.025 m0.020 mfrom file
Support structure->Tubular tower Bottom diameter6 m8.3 mfrom file
Support structure->Tubular tower Bottom thickness0.035 m0.038 mfrom file

Note: two different DTU 10-MW blades are shipped with Ashes, that can be found in the Blade database, corresponding to the blades with and without pre-bending in Bak et al. (2013). Note that the blade without prebending (called DTU 10-MW (no prebend) in Ashes) has a prebending in the in-plane direction. This is due to the definition of the airfoils and the blade in Bak et al. (2013): since the Blade reference line does not go through the Aerodynamical reference point, an in-plane offset is necessary, which results in an in-plane prebending in Ashes.

In addition, we also ship DTU blades with modified polars in the inner part of the blade to deal with the Dynamic stall issue at low wind speeds (see section 4 of the DTU 10-MW document).

Note: in the specification document for the IEA 15-MW, it is said that the center of mass of the nacelle is downwind with respect to the yaw axis. Since the IEA 15-MW is a direct drive wind turbine, it seems like the center of mass of the nacelle should be upwind. We assume that this is a typo in the specification document and have set the center of mass of the nacelle to be upwind

Note: no information is given in the specifications about the shaft dimensions. Therefore, for the NREL 5-MW and the DTU 10-MW models, we have selected values that produce a correct 1st drivetrain torsion mode (see OC3 Phase I load case 1.2 and ). We have not found information for the 1st drivetrain torsion mode for the IEA 15-MW, therefore the values are somewhat arbitrary.