IEC 61400 1 Edition 3 1 2014 04 CONSOLIDATED VERSION Wind turbines – Part 1 Design requirements IE C 6 14 00 1 2 00 5 08 +A M D 1 20 10 1 0 C S V (e n) ® colour inside C opyrighted m aterial licensed[.]
Symbols and units
C scale parameter of the Weibull distribution function [m/s]
C CT turbulence structure correction parameter
D rotor diameter [m] f frequency [s –1 ] f d design value for material strength [-] f k characteristic value for material strength [-]
I ref expected value of hub-height turbulence intensity at a 10 min average wind speed of 15 m/s [-]
I eff effective turbulence intensity [-] k shape parameter of the Weibull distribution function [-]
L isotropic turbulence integral scale parameter [m]
L k velocity component integral scale parameter [m] m Wửhler curve exponent [-] n i counted number of fatigue cycles in load bin i [-]
N(.) is the number of cycles to failure as a function of the stress (or strain) indicated by the argument (i.e the characteristic S-N curve) [-]
N recurrence period for extreme situations [years] p survival probability [-]
P R (V 0 ) Rayleigh probability distribution, i.e the probability that V