## Search found 52 matches

Mon May 10, 2021 5:03 am
Forum: Rotor Aerodynamics
Topic: Determing rated wind speed
Replies: 1
Views: 375

### Determing rated wind speed

Dear all. Issue : Difference in the rated wind speed determined using formula (1) and formula (2). I am working on WP1.5MW turbine. I have generated power curve using OpenFAST using the grid resolution: Tip speed ratio—0.061; Pitch — 0.1 deg. The optimal point on power surface plot: Tip speed ratio ...
Thu Apr 29, 2021 1:21 pm
Forum: Controls
Topic: Power coefficient/Aerodynamic torque
Replies: 21
Views: 5816

### Re: Power coefficient/Aerodynamic torque

Dear Jason, I have made sure that all the parameters are the same between both AeroDyn (stand alone version) and AeroDyn in OpenFAST. But still I see significant difference between the Aerodynamic Power calculated using standalone Aerodyn vs OpenFAST. Wind speed (m/s) Pitch (deg) Rotor speed (RPM) R...
Thu Apr 22, 2021 2:26 pm
Forum: Controls
Topic: Power coefficient/Aerodynamic torque
Replies: 21
Views: 5816

### Re: Power coefficient/Aerodynamic torque

Dear all, Issue: Difference in the aerodynamic power of rotor between Standalone AeroDyn calculation and OpenFAST calculation. I have calculated Rotor aerodynamic power for WindPact 1.5MW turbine at (pitch=2.2 deg, rotor speed=24RPM, wind speed=12 m/s Uniform) using 1) Standalone version of AeroDyn1...
Mon Apr 19, 2021 8:16 am
Forum: Controls
Topic: ROSCO-MATLAB Implementation
Replies: 28
Views: 1781

### Re: ROSCO-MATLAB Implementation

Dear Shubham,

Check if you can find what you are looking for here: https://github.com/NREL/ROSCO/tree/cffa ... f3df92/src

Regards,
Kumara
Wed Apr 14, 2021 11:58 pm
Forum: Controls
Topic: ROSCO-MATLAB Implementation
Replies: 28
Views: 1781

### Re: ROSCO-MATLAB Implementation

Thank you, Nikhar. I will go through the referred article and revert incase of any queries.

Regards,
Kumara
Tue Apr 13, 2021 2:05 pm
Forum: Controls
Topic: ROSCO-MATLAB Implementation
Replies: 28
Views: 1781

### Re: ROSCO-MATLAB Implementation

Dear Nikhar, Are there any technical papers that I can refer to understand the technical aspects of the controller design used in the ROSCO.mdl. I have gone through the Jupyter note book, but, I am looking fore more details like the "Wind speed estimation algorithm" etc. Another general qu...
Thu Jan 28, 2021 11:17 am
Forum: Controls
Topic: WindPact 1.5MW pitch range
Replies: 1
Views: 546

### WindPact 1.5MW pitch range

Dear all, Is WindPact1.5MW (WP1.5MW) with the default data given in CertTest folder that comes with FAST designed for "Pitch to feather" or "Pitch to stall"? What is the typical range of Pitch motion for Pitch to feather 1.5MW turbine? I have generated power curve (surface) using...
Mon May 04, 2020 4:17 pm
Forum: Computer-Aided Engineering Software Tools
Topic: LARGE DISCREPANCY BETWEEN MY RESULTS AND THOSE FFROM FAST
Replies: 26
Views: 8702

### Re: LARGE DISCREPANCY BETWEEN MY RESULTS AND THOSE FFROM FAST

Dear Jason,

Regards,
Kumara
Sat May 02, 2020 5:09 pm
Forum: Computer-Aided Engineering Software Tools
Topic: LARGE DISCREPANCY BETWEEN MY RESULTS AND THOSE FFROM FAST
Replies: 26
Views: 8702

### Re: LARGE DISCREPANCY BETWEEN MY RESULTS AND THOSE FFROM FAS

Dear Arash, Aerodynamic damping is not directly specified in the FAST input files,.... but is included intrinsically as part of the aero-elastic solution. That is, the aerodynamic force calculated within FAST is dependent on the structural velocity. In your mathematical model, the aerodynamic force...
Sun Mar 01, 2020 6:48 am
Forum: Structural Analysis
Topic: RK4 implementation
Replies: 2
Views: 1189

### Re: RK4 implementation

Dear Jason,

It was a bug in my code causing the trouble. Fixed it. Now I am able to get meaningful results with 0.02s (about 1/10 of the period corresponding to highest frequency) .
Sorry for the trouble.
Regards,
Kumara
Sat Feb 29, 2020 12:00 am
Forum: Structural Analysis
Topic: RK4 implementation
Replies: 2
Views: 1189

### RK4 implementation

Dear all, I have written MATLAB code to simulate wind turbine. I have considered only one mode (fore-aft) of tower and verified results with FAST simulation results. They are agreeing reasonably well. In this case I have used RK4 numerical integration in both MATLAB and FAST with a time step of 0.05...
Sat Dec 28, 2019 1:00 pm
Forum: Rotor Aerodynamics
Topic: Help about BEM and NREL's Phase VI
Replies: 41
Views: 19294

### Re: Help about BEM and NREL's Phase VI

Yes Jason, i meant "phi" not 'x'. My main concern is how to deal with the case of a=1, and a' = -1; I understand your comments on Vx, Vy. Since I'm looking at the simple case of rigid blades, I'm using V_wind and r*Omega instead of Vx, Vy. Could you please tell me how are these exceptional...
Thu Dec 26, 2019 1:38 pm
Forum: Rotor Aerodynamics
Topic: Help about BEM and NREL's Phase VI
Replies: 41
Views: 19294

### Re: Help about BEM and NREL's Phase VI

Dear all,

Should the induction factors (a, a') and inflow angle (phi) obtained from FAST, satisfy the below equation always? I am using OpenFastV2.2.0.

[sin(phi) / (1 - a) ] - [ (V_wind/V_r)*cos(x) / (1 + a') ] = 0
where V_r = r*Omega_r;

Regards,
Kumara
Fri Dec 20, 2019 3:31 am
Forum: Rotor Aerodynamics
Topic: Help about BEM and NREL's Phase VI
Replies: 41
Views: 19294

### Re: Help about BEM and NREL's Phase VI

Dear Jason, I went through the source code ( inductionFactors subroutine, BEMTUncoupled module ) again. Now I understand the reason for defining 'a' twice (before and after the evaluation of residual). It is because Residual calculations (which are performed in later part of the code) require the va...
Wed Dec 18, 2019 1:52 pm
Forum: Rotor Aerodynamics
Topic: Help about BEM and NREL's Phase VI
Replies: 41
Views: 19294

### Re: Help about BEM and NREL's Phase VI

Dear Jason, I have one more question. In the source code corresponding to the propeller brake region, (Copied below) after setting IsValidSolution =.false, why to assign value to a? Because at another portion in the source copied below (with blue color text) a and a' are assigned as zeros. ? Please ...