OC4 Phase I load case 1.0b
1 Test description
In this load case, we compare the eigenfrequencies of the OC4 Phase I model between Ashes and the participants of the project. The data from the participants can be seen in figure 4 from
The mode is the NREL 5-MW reference wind turbine mounted on the OC4 Jacket, as defined in
It can be recreated using the offshore template and using the CSV file available here.
The eigenfrequences of the model are solved and compared to those presented in the OC4 Phase I project. Note that the numbering of the eigenfrequencies in Ashes is from the lowest frequency to the highest, which is not the same as in the OC4 Phase I project. The table below summarises the numbering correspondance.
|Mode number in Ashes||Mode name||Mode number in OC4 Phase I|
|1||1st global side-to-side||2|
|2||1st global fore-aft||1|
|3||1st drivetrain torsion||3|
|4||1st asymetric flapwise yaw||5|
|5||1st asymetric flapwise pitch||4|
|6||1st flapwise collective||6|
|7||1st asymetric edgewise yaw||8|
|8||1st asymetric edgewise pitch||7|
|9||2nd global fore-aft||10|
|10||2nd glbal side-to-side||11|
|11||2nd asymetric flapwise yaw||12|
|12||2nd asymetric flapwise pitch||13|
|13||2nd flapwise collective||14|
|14||1st edgewise collective||16|
|15||1st global torsion||15|
A bar plot with the eigenfrequencies from the different participants in the OC3 Phase II project and from Ashes is available on the following link.
Note that only a visual check is performed in that report. Once we have a set of results that are in agreement with the other participants, we use that set as a base case to compare the results produced by Ashes daily. If these results differ from more than 0.01% with the base, a failed test notification is raised. The report can be found on the following link: