What is the reason behind the six realizations

Wind & Water Structural Analysis
1

Dear wind turbine enthusiasts,

I was wondering whether anyone knows what is the reason behind the six realizations recommended by the standards (IEC, DNV) ? I mean why six ? why not 50 ? Is there any study about the number of stochastic realizations ?

Also, why it is recommended to do 10 minutes for fixed-bottom wind turbines ? Is there any study about the duration of the simulation ?

Thanks in advance.

Best Regards,

Riad

2

Dear @Riad.Elhamoud,

The 10-minute simulation length used commonly in wind energy is historical and derives from the understanding that wind conditions on average can be considered stationary over this period. Of course, wind may remain stationary for less or more time for any given situation.

Six realizations is also historical, and derives from a balance between convergence of statistics and being sufficient enough given the use of safety factors and elevated levels of turbulence in design. There are many papers in the literature demonstrating that more than six realizations is needed for statistical convergence.

Best regards,

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