Dear Jason,
Thank you!
Now, it is clear to me.
Best regards,
Cheng
Dear Jason,
I have a controller that reduced the platform roll by -20% and platform pitch rate by -25% comparing with GSPI.
But the DEL of tower base side-to-side and fore-aft moment almost same as GSPI. Is it normal?
best regards,
Cheng
Dear Cheng,
That sounds a bit strange, but I’m not sure I can comment on that for a general system.
Best regards,
hi mr jonkman
Error reported by S-function ‘FAST_SFunc’ in ‘OpenLoopA/FAST Nonlinear Wind Turbine/S-Function’:
FAST_Solution:FAST_AdvanceStates:AD_UpdateStates:BEMT_UpdateStates(node 3, blade 3):BEMT_UnCoupledSolve:DeterminePhiBounds:There is no valid value of phi for these operating conditions! Vx = 1.8524, Vy = -10.139, rlocal = 5.1167, theta = 0.42312
What is this error related to?
How to fix it?
thanks
Dear Zarei,
There were issues in AeroDyn v15.03 within FAST v8.16 that led to the error “no valid value of phi” in some cases. However, these issues have been fixed in AeroDyn v15.04 and newer in OpenFAST. I suggest you upgrade to OpenFAST: github.com/OpenFAST/openfast/pull/204.
Best regards,
thanks for your answer
I download AeroDyn v15.04 but the AeroDyn Input file related to Test 11-14 (1.5 MW Wind turbine) does not exist. How to find it?
Hi mr jonkamn.
I simulated 5 MW wind turbine with " Definition of a 5-MW Reference Wind Turbine for Offshore System Development ". When my input wind is in partial load region, I got logical results but when input wind is in full load region, the results look like these:
Can you tell me if these power and generator torque diagrams seem correct? Can power be constant?
Thanks.
Dear Hamidreza,
The baseline controller for the NREL 5-MW turbine uses a constant power above rated; i.e. the generator torque is inversely proportional to the generator speed such that the power (= torque*speed) is constant.
It looks like in your simulation you have an exaggerated start-up transient likely due to poor initial conditions; in general, I suggest initializing the rotor speed and blade-pitch angles to their expected mean values for a given mean hub-height wind speed.
Best regards,
Thanks for your reply.
so except the initials, is this power curve correct? can it be without any oscillations around 5MW reference?
Dear Hamidreza,
I assume you are using steady and uniform wind inflow? In this case, I would expect the power and torque to be constant after the start-up transient. It looks like the power is constant and the torque is heading that way. It would also be informative to plot the rotor speed and blade-pitch angle.
Best regards,
Thanks for your attention
I use Binary TurbSim Full-Field Wind for my case.
wind speed, Rotor Speed and Blade-Pitch angle are as below:
Dear Hamidreza,
Your power has an odd start-up transient because you have not initialized the blade-pitch angle properly. In general, to minimize the start-up transient, I recommend that you initialize the rotor speed and blade-pitch angles to their expected values for the given mean wind speed. For 18 m/s, this would be RotSpeed = 12.1 rpm and BlPitch = 14.92 deg for the NREL 5-MW baseline turbine, per its specifications report: nrel.gov/docs/fy09osti/38060.pdf. Otherwise, the response is as I would expect it to be.
Best regards,
Thanks.
My initial Rotor Speed is 12.1 rpm . but when i tried to set initial blades pitch to 14.92 degree i got this error:
indeed only with 0 degree blade pitch simulink runs
Dear Hamidreza,
Which version of FAST / OpenFAST are you using? There have been many bug fixes made to BeamDyn over the past couple of years. When running BeamDyn, I would suggest using the newest version of OpenFAST (dev branch).
Best regards,
I’m using FAST_v8.16
Hopefully upgrading to OpenFAST-dev will eliminate the BeamDyn problems you are facing.