Hi @Jason.Jonkman:
Noted. Thank you.
I have sent you an email. I would be grateful if you would provide a response.
Regards,
AOAW
Hi @Jason.Jonkman:
Is the fore-aft moments at the base of the tower (TwrBsMyt) usually greater than the side-side moments at the base (TwrBsMxt). I did a simulation of an idle turbine using the DTU 10MW reference wind turbine and the maximum fore-aft moment over the simulation is less than max side-side moment. I find this strange as I was expecting the opposite to happen, based on what I saw from a paper. When I simulated the operating condition at rated wind speed, the maximum fore-aft moment was greater than the maximum side-side moment, as expected. Maximum here is the absolute maximum.
Please let me have your feedback as I am not sure if I am doing something wrong causing the fore-aft moments to be less than they should be for the idle turbine.
Regards,
AOAW
Dear @Andre.White,
During operation, I would expect the tower-base fore-aft moment to exceed the tower-base side-side moment because the thrust times tower height typically exceeds the generator torque.
During idling with active yaw control and the blades feathered, I would expect aerodynamic loads on the rotor to be small, and aerodynamic loads on the tower to dominate.
During idling with the blades feathered but loss of yaw control, the loads are likely heavily dependent on yaw-misalignment and you have to watch out for blade-edgewise / tower side-side instabilities.
Best regards,
Thanks @Jason.Jonkman .
Regards,
AOAW
Hi @Jason.Jonkman:
Regarding the wind veer parameter, it states that it is given in a counterclockwise direction. Does this mean I have to change the sign to make degrees negative or do I have to subtract from 360 degrees?
When I run the DTU model and include the veer angles it causes the deflection on the blades to decrease. Trying to find out why this is so and how I could fix it.
Regards,
AOAW
Hi @Jason.Jonkman besides the blade structural damping, is there any other parameter that could result in lower blade tip deflection than expected?
Regards,
AOAW
Dear @Andre.White,
Regarding veer, using a positive sign for counter-clockwise angles from above and use a negative sign for clockwise angles from above.
I’m not sure I understand your question regarding blade deflection.
Best regards
Thank you @Jason.Jonkman. What I was asking is if the blade structural damping value can alter the blade tip deflections. If this is so (or not), are there other parameters that could alter blade tip deflections.
Regards,
AOAW
Dear @Andre.White,
Certainly the blade structural damping could influence the deflection because damping can temper resonance or instabilities. Blade mass, stiffness, and aerodynamic loads would also influence the deflection.
Best regards,
1 Like
Thanks Jason.
Regards,
AOAW
Hi @Jason.Jonkman:
Is there a way to show the difference in wind conditions in TurbSim? For example, if I use a power law profile, wind speed at hub height and turbulence intensity, how can I show that it differs from a user-defined wind shear profile (which includes veer), and a value for the coherence exponent. What I want to find out is if I enter a wind speed and TI only in TurbSim, as compared to a user defined wind shear profile with veer and coherence exponent, how can I show that both those wind conditions which will be applied to an OpenFAST model are different.
Hope I am clear.
Thank you.
Regards,
AOAW
Dear @Andre.White,
I’m not fully sure I understand what you are asking, but the wind speed profile with height is written to the TurbSim summary file. And you could always visualize the full turbulent wind field, for example, using the script readfile_BTS.m from the MATLAB Toolbox: matlab-toolbox/Utilities at main · OpenFAST/matlab-toolbox · GitHub.
Best regards,
Thanks @Jason.Jonkman.
I was actually asking if I entered one condition in TurbSim as a normal wind condition (TI and wind speed at hub height) and the other as hurricane conditions, how I would be able to see or establish the difference.
Regards,
AOAW
Hi @Jason.Jonkman:
When you say visualize, do you mean there is a way to see an image of the full turbulent wind field?
Regards,
AOAW
Dear @Andre.White,
Regarding visualization of the TurbSim wind field, yes you can do that. For example, see the discussion in the following forum topic: Visualize full-field Turbsim data and anemometer equivalent wind speed.
I’m not sure I understand your other question about normal versus hurricane conditions.
Best regards.
Thanks @Jason.Jonkman.
Is it the FFWind function that is used to visualize the wind field?
For normal conditions I mean, say rated wind speed and TI. For hurricane conditions I mean, higher wind speed, say 65 m/s, TI, user-defined windshear profile, for the particular hurricane and a value for the coherence exponent.
Regarding the summary file, can that be used to show the difference? Never used the summary file before so I am not sure how to use it to differentiate between wind fields.
Regards,
AOAW
Dear @Andre.White,
Yes, I was referring to the FFwind_figure.m script.
All I meant regarding the summary file is that it will show you the mean profile used.
I’m still not sure I understand what you are asking regarding differing conditions.
Best regards,
Hi thanks @Jason.Jonkman.
Let me try again. If I use two different sets of wind conditions in a OpenFAST model, how can I show that the wind conditions are different without only depending on the values entered in TurbSim alone. I want to actually show that the wind conditions used are different.
Regards,
AOAW
Dear @Andre.White,
You can do as we already discussed–visualize the wind field or shear profile.
You can also output wind at multiple points from the OpenFAST simulation (up to 9 user-selected points in InflowWind).
Best regards,
Hi @Jason.Jonkman thank you. I have one more question, would FFwind also allow me to visualize the wind shear profile?
Regards,
AOAW