Mr. Jonkman hi,
I ecountered some problems which I still haven’t solved and I would appreciate your help.
First of all, I use your 5-MW offshore wind turbine as a model. I modified it for my site (15m depth, 92.6m Hub height, tower height 77.6m). So, as you can see the differences are just small. I created wind files using TurbSim for wind speeds (4 different load cases):
1)11.4 m/s (ETM)
2)25 m/s (ETM)
3)41.6 m/s (NTM)
4)43.7 m/s (NTM)
I now use FAST_v7.02.00d-bjj_AeroDyn_v13.00.02a-bjj_BladedDLLInterface with all your files included and my wind files in it. I modified just a few things due to my different structure.
- case works well with no problems at all. The 3 other cases all have a warning message
WARNING: Small angle assumption violated in SUBROUTINE SmllRotTrans() due to a large blade
deflection. The solution may be inaccurate. Simulation continuing, but future warnings will be
suppressed.
Time step is 0.0125 and tried 0.00125 too in 630 sec simulation. The grid width-height in TurbSim are 145m
Maybe the warning is due to sudden loading of blades as mentioned above?
Also another problem I encountered is that even with a wind speed of 41.6 m/s at hub height somehow the turbine still works and generates power.
Time_____WindVxi____WindVyi_____WindVzi______WaveElev___GenPwr_______GenTq_______OoPDefl1____IPDefl1
(s)(m/s)(m/s)(m/s) (m)(kW)(kN·m)(m)(m)
30.000___4.183E+01__5.555E-01-6.911E+00__-1.536E-01___4.928E+03____4.365E+01____-4.981E-01___3.213E-01
30.013__4.164E+01___3.778E-01____-6.593E+00___-1.524E-01___4.923E+03____4.366E+01____-4.763E-01___2.920E-01
30.025__4.173E+01___3.102E-01____-5.903E+00___-1.512E-01___4.918E+03____4.367E+01____-4.541E-01___2.624E-01
30.038__4.182E+01___2.426E-01____-5.214E+00___-1.500E-01___4.912E+03____4.368E+01____-4.310E-01___2.323E-01
30.050__4.192E+01___1.750E-01____-4.525E+00___-1.488E-01___4.908E+03____4.370E+01____-4.080E-01___2.026E-01
…
335.775__4.483E+01__-1.832E+00___-1.745E+00___1.972E+00___5.041E+03____4.572E+01____-1.358E+00___1.753E+00
…
406.400__3.852E+01__-4.748E+00___-1.277E+00___4.940E-02___4.865E+03____4.579E+01____-1.230E+00___1.426E+00
…
593.513__4.830E+01__3.494E+00____-6.235E-01___2.945E-01___4.946E+03____3.875E+01____-3.824E+00___3.580E+00
Shouldn’t the turbine be offline since the wind speed has by far surpassed the cut-out speed?
I’m sorry if my question is dumb, but I really don’t know where to look for this kind of problem.
Best regards,
Thanasis Petridis