the cause of the 1p loading on the blade

Hello everyone,

I know that the rotational sampling of turbulence and tower shadow and wind shear will lead to the 1p load on the blade. But I don’t know which factor is the main cause of the 1p load on the blade, turbulence or tower shadow? I was told the turbulence plays the main role in the 1p load on the blade and the 3p load on the hub and tower, so to examine this I have done some simulations under turbulent wind speed , however the results show that the tower shadow is the main cause. Could anybody help me confirm this?
Thanks in advance.

Best regards,
Yunqian Zhang

Dear Yunqian,

I have never actually tested this, but it would be pretty trivial for you to test it.

Your homework assignment :slight_smile: is to make three FAST runs. For the first run, enable the tower shadow, and use a hub-height wind file with constant winds and no shear. For the second, disable the tower shadow and change the shear in the HH file to 0.14. For the third run, generate a custom TurbSim file with no shear and run FAST with no tower shadow. See which causes the largest 1P effect.

Please keep in mind that this will depend on the turbine, the choice of shear, turbulence intensity, and the mean wind speed. Maybe you need to make dozens of runs with different turbines. :stuck_out_tongue:

I would greatly appreciate it if you would post your results here. :slight_smile:

Dear Marshall,

Thanks for your response. I have done the simulation on the 1.5MW reference wind turbine as you suggeted. The simulation results are attached.

Yes, the results change with kinds of factors you mentioned. So it’s hard to say which factor is the main cause of the 1p loading on the blade.

Thanks again.

Best regards,
Yunqian Zhang

Hello everyone,

I am trying to derive simulated response data from the 5MW baseline turbine using FAST v7.02, including 1P, 3P, 5P, … loading. Which would be the best way to include this effect?

Thank you very much!

Best regards


Dear Georgios,

Due to the rotational sampling of turbulence by a spinning rotor blade, a blade will be excited by 0P, 1P, 2P, 3P, etc. (in a frame of reference that rotates with the blade) when the wind turbine is operating in turbulence. All you need to do is generate turbulent wind inflow e.g. using TurbSim and simulate with that wind data in FAST.

Best regards,