Tidal Bladed Knowledge Base

IEC Ultimate load sub groups
Category: Post Processing

Problem
I would like to perform post processing of ultimate loads following the IEC 61400-1 standard. For this kind of post processing it is important to introduce sub groups in order to create the “mean of max” (or the “mean of top half”) of  different time series belonging to one wind speed bin but differ in seeds.
Solution

It’s possible to name your simulations and folders in such a way that makes post-processing using the IEC sub groups easier.

Firstly, we suggest that you use folder names which correspond to the load cases which you would like to apply safety factors to. Each of these folders would contain the simulations which are associated with that load case. This would mean that you only have to create one group for each DLC to apply the safety factor.

Example folder structure

Example set up in load case group window.

Then you should name your simulations so that the names are identical over all seeds which you would like to average over except for a number after the identifier (In the example above I’ve used – for the mean type sub group, and + for the mean of the top half group)

So, if you are simulating 6 wind seeds for one wind speed bin and you would like to average over these seeds you might name them as shown below. The simulations named eaa-1 to eaa-6 are all for the same wind speed bin (e.g. wind speed of 5m/s), the only difference is the wind file used. 

When all simulations are ready you can then add them the load cases window. The load case group should be automatically picked up and displayed and if you press the ‘update sub groups’ button then the sub group type will be populated. 





Keywords Post processing; ultimate loads; sub groups