Search found 18 matches

by Sam.Ramsahoye
Fri Jul 31, 2020 2:44 am
Forum: Controls
Topic: Individual Pitch Control
Replies: 6
Views: 240

Re: Individual Pitch Control

Hi Nikhar,

Thanks for you reply, I'll take a look.

Best wishes,
Sam
by Sam.Ramsahoye
Mon Jul 27, 2020 9:58 am
Forum: Controls
Topic: Individual Pitch Control
Replies: 6
Views: 240

Individual Pitch Control

Hi, I noticed that there is some individual pitch controller functionality with the ROSCO controller interface. Can someone link the theory for this controller so I can compute sensible inputs/gains? !------- INDIVIDUAL PITCH CONTROL ----------------------------------------- 0.0 ! IPC_IntSat - Integ...
by Sam.Ramsahoye
Wed May 27, 2020 6:18 am
Forum: Controls
Topic: ROSCO Toolbox - Relationship Between Integral Gain & Damping of Fore-Aft Mode
Replies: 2
Views: 343

Re: ROSCO Toolbox - Relationship Between Integral Gain & Damping of Fore-Aft Mode

Hi Nikhar,

Thanks very much, think I've got it working now.

Best,
Sam
by Sam.Ramsahoye
Tue May 26, 2020 4:06 pm
Forum: Controls
Topic: ROSCO Toolbox - Relationship Between Integral Gain & Damping of Fore-Aft Mode
Replies: 2
Views: 343

ROSCO Toolbox - Relationship Between Integral Gain & Damping of Fore-Aft Mode

Hi,

Is there an analytical relationship between the integral gain on the fore-aft damper and the damping of the fore-aft mode in the ROSCO controller? I'm trying to reduce tower-fatigue.

Best wishes,
Sam
by Sam.Ramsahoye
Thu May 21, 2020 7:06 am
Forum: Rotor Aerodynamics
Topic: Unsteady Aerodynamics Turning Off
Replies: 1
Views: 241

Unsteady Aerodynamics Turning Off

Hello,

I'm getting warning messages saying unsteady aerodynamics have been turned off. Does this new condition without unsteady aerodynamics persist for the entirety of the simulation?

Could this explain why my power, thrust curves appear to be insensitive to turbulence intensity?

Best wishes,
Sam
by Sam.Ramsahoye
Thu May 14, 2020 1:55 pm
Forum: General
Topic: Turbulent Power Curves
Replies: 3
Views: 334

Re: Turbulent Power Curves

Hi Jason, Thanks so much for your assistance. I believe your understanding is correct. I've running wind-only aero-elastic simulations with a TSR-tracking controller in the region 2 in order generate power and thrust curves for different turbulent intensities and plotting as a function of wind-speed...
by Sam.Ramsahoye
Thu May 14, 2020 10:50 am
Forum: General
Topic: Turbulent Power Curves
Replies: 3
Views: 334

Turbulent Power Curves

Hello, I've evaluated a "pseudo-steady" power curve for a turbine using a Taylor's series approach with turbulence intensity for different wind speeds. I was provided with power/thrust curves for a range of different wind speeds and quoted turbulence intensities. My back-calculated steady-...
by Sam.Ramsahoye
Thu May 07, 2020 3:23 pm
Forum: Controls
Topic: ROSCO Equivalent Wind Speed Estimator Struggling Due to Blade Deflection
Replies: 7
Views: 678

Re: ROSCO Equivalent Wind Speed Estimator Struggling Due to Blade Deflection

Hi Nikhar, Sounds good. I was thinking of running constant TSR under rated and constant power above, seems like that's an easy change to the source code I can make if it is worth while. My main motivation had been that power curves tend to be flat after rated conditions. But perhaps controllers base...
by Sam.Ramsahoye
Thu May 07, 2020 2:08 pm
Forum: Controls
Topic: ROSCO Equivalent Wind Speed Estimator Struggling Due to Blade Deflection
Replies: 7
Views: 678

Re: ROSCO Equivalent Wind Speed Estimator Struggling Due to Blade Deflection

Hi Nikhar, Thanks for the assistance! If I was to make ti a user input variable, do you think it would actually improve the quality of my results? Also, will VS_ControlMode = 2 strictly try and enforce that the tip-speed ratio is constant up to rated speed, or rated-speed and beyond? From what I can...
by Sam.Ramsahoye
Thu May 07, 2020 11:50 am
Forum: Controls
Topic: ROSCO Equivalent Wind Speed Estimator Struggling Due to Blade Deflection
Replies: 7
Views: 678

Re: ROSCO Equivalent Wind Speed Estimator Struggling Due to Blade Deflection

Hi Nikhar,

I edited my original reply for clarity. I added a question relating to turbulence intensity in the WSE.

Thanks,
Sam
by Sam.Ramsahoye
Thu May 07, 2020 10:15 am
Forum: Computer-Aided Engineering Software Tools
Topic: OpenFAST Simulation Time Ratio (Sim/CPU)
Replies: 1
Views: 282

OpenFAST Simulation Time Ratio (Sim/CPU)

Hi, Does anyone have any recommendations for faster simulation times? I've currently compiled everything inside an Ubuntu-based Docker container. Is speed compiler dependent? At the moment I can get around 0.333-0.5 on Sim/CPU. Can one sacrifice accuracy on small time/spatial scales but still be con...
by Sam.Ramsahoye
Thu May 07, 2020 9:54 am
Forum: Controls
Topic: ROSCO Equivalent Wind Speed Estimator Struggling Due to Blade Deflection
Replies: 7
Views: 678

Re: ROSCO Equivalent Wind Speed Estimator Struggling Due to Blade Deflection

It was my openfast naivety which was the problem, nothing to do with the ROSCO_toolbox or the ROSCO controller. Updating the LinearRamp setting to true in ServoDyn and adding a corrector iteration in the driver stabilised things. I noticed in the source code for the wind-speed estimator that there i...
by Sam.Ramsahoye
Thu May 07, 2020 6:42 am
Forum: Controls
Topic: ROSCO Equivalent Wind Speed Estimator Struggling Due to Blade Deflection
Replies: 7
Views: 678

ROSCO Equivalent Wind Speed Estimator Struggling Due to Blade Deflection

Hi, I'm having some problems getting the extended Kalman filter (WE_Mode=2) to work reliably when I enable the blade degrees of freedom. I find that reliable estimates are obtained with rigid blades and that the divergence between reliable and unreliable esimates (obtained with flexible blades) is w...
by Sam.Ramsahoye
Thu Apr 30, 2020 12:15 pm
Forum: Structural Analysis
Topic: 15MW Reference Turbine - ElastoDyn + BeamDyn Blades
Replies: 1
Views: 337

15MW Reference Turbine - ElastoDyn + BeamDyn Blades

Hi, For such a large turbine with composite blades and bending/twist coupling, when can one get away with just using ElastoDyn for their simulation? If one is ultimately interested in foundation loads, are differences between the two ultimately smoothed out in macroscopic characteristics of the foun...
by Sam.Ramsahoye
Thu Apr 30, 2020 12:01 pm
Forum: Controls
Topic: Pitch Control Before Rated Speed
Replies: 5
Views: 628

Re: Pitch Control Before Rated Speed

Hi Nikhar, Thank you very much for replying, I really appreciate it. I ended up having a look at the source code in the NREL_toolbox to find out what it was doing. To evaluate my peak shaving parameter all I had to do was evaluate the thrust coefficient in steady-state at rated conditions with no pi...

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