Approximate root moments for coned/tilted rotor

Wind & Water Rotor Aerodynamics
1

Hello NREL forum,

Is there a way to approximate the blade root moments (out-of-plane/in-plane) of a tilted rotor with preconed blades, if I have available as output the blade root moments/forces of a simulation with zero tilt & precone. I know it won’t be accurate since these two angles won’t have been considered during the simulation, but I am looking for the extra force contributions that could be added such as to approximate as far as possible a tilted/coned rotor. I ran 2 cases in FAST and the in-plane moments do not differ much, but the out-of-plane have big deviation. So, I am most interested in the latter.

Best wishes,
Jack M.

2

Dear Jack,

I’m not aware of simplified equations that would well approximate the effects of precone and tilt. You’d have to consider the effect of the tilt and precone on the local aerodynamic inflow and its effect on the aerodynamic applied loads, as well as structural effects such as the change to centrifugal and gravity loads. Because the loads are changing, the aero-elastic response would also change.

Best regards,