NREL 5MW Rotor Geometry

Wind & Water Rotor Aerodynamics
21

Dear @Yao.Tian,

Being a reference wind turbine, there are many publications showing simulation results of the NREL 5-MW baseline wind turbine. Can you clarify what type of simulations you are considering?

The NREL 5-MW baseline wind turbine is not a real turbine, so full-scale measurements do not exist. There are many model-scale versions of the NREL 5-MW baseline turbine, where experimental data exist, but all of these have some variations relative to the original specification.

Best regards,

1 Like
22

Dear @Jason.Jonkman

Thank you for your reply. I am studying the distributed force of the blade, the deformation of the blade and the flow characteristics of the wind turbine wake under various operating conditions of the NREL 5MW wind turbine. I would be grateful if you could recommend me some widely cited papers, or provide some experimental data on the relevant part.

Best regards，

23

dear @Jason.Jonkman

I’ve found some papers, which are very useful. Thanks all the same.

Best regards

1 Like
24

can you send me a copy of them

25

For CFD, can you please provide, raduis, chord lenght, axis location, twist angle, pitch and what is the raduis of the wind turbine blade for CFD

26

I have made this table. Dear @Jason.Jonkman can you please confirm it?

77aea6a1-badf-4209-95e0-89f7ca04fe2a
77aea6a1-badf-4209-95e0-89f7ca04fe2a760×526 132 KB

27

Dear @Sijal.Ahmed,

It is hard to compare to values shared through a picture. The values in your table generally look correct, but I would suggest plotting the data on top of the data published by NREL.

Best regards,

28

These are exactly same value published by the your report. But only thing that I added is the pitch axis locatino from leading edge by interpolating for first four locations. Afterwards all airfoils are at 0.375 m from leading edge for the 1 m chord airfoils.
One more thing which is making me confused is that, people in litrature refer to raduis of 61.5 m (stations 17). so which one one is correct one I pasted above or last raduis is 61.5 m which actually makes the blade raduis = 63 m and diamter = 126 m

29

For CAD model we should follow this or the one given here
image

30

Dear @Sijal.Ahmed,

The difference between 61.5 m and 63 m is the hub radius of 1.5 m; i.e. the blade root starts at radius of 1.5 m.

Best regards,

31

Thanks. @Jason.Jonkman for clarification. I found some resources and they may be helpful.
First one is from Qblade 5 MW wind turbine example:

a
a1017×817 13.1 KB

b
b464×682 23.4 KB

The second reference is from SANDIA report
Definition of a 5MW/61.5m Wind Turbine Blade Reference Model by Brian R. Resor
SANDIA

The original reference model properties:

c
c562×736 43.1 KB

The model adjusted by the SANDIA

d
d621×879 65.6 KB

Please note that, pitch axis in orignal data is at 0.375 m for station no. 5 and onwards. While in SANDIA is 0.4 m (for 1 m chord airfoils, adjusted at 40% of chord lenght fo respective chord lengths)

32

@Jason.Jonkman Is it possible to publish design data (for CAD and CFD modeling) that is without any confusion?

33

Dear @Sijal.Ahmed,

Regarding a CAD or surface mesh for CFD simulations for the NREL 5-MW baseline wind turbine, see a similar question that was asked and answered in the following forum topic: NREL 5 MW - Blade Airfoils Data Files AR17.

Best regards,

1 Like
34

Dear @Jason.Jonkman
Assuming the aerodynamic center of the airfoil coincides with the pitch axis, and both the blade precone(1-3) and ShftTilt angle are zero with no yaw, I have the following three questions:

(1) In the coordinate systems shown in the figure below, which is the blade coordinate system in ElastoDyn module, and which is the local blade coordinate system? In the horizontal direction, there are two pairs of X and Y axes: X1 and Y1 in red, and X2 and Y2 in black (parallel to the local chord). In the vertical direction, there are three pairs of X and Z axes: X1 and Z1 in red, X2 and Z2 in black, or X3 and Z3 in blue. The differences among them lie in the origin and whether they are based on the deformed pitch axis. Because I found that the definitions of the two coordinate systems mentioned above differ somewhat between the FAST and aerodynamics user’s manuals https://openfast.readthedocs.io/en/main/source/user/aerodyn/input.html#blade-data-input-file, which have caused some confusion for me.
Here is the format of the answer for reference. The combination of X1 and Y1, and X3 and Z3 is the blade coordinate system, with the combination of X2 and Y2, and X2 and Z2 representing the local blade coordinate system, however which is not the answer itself.

CS
CS1001×461 58.5 KB

（2）Is the reference point for the airfoil pitching moment coefficient the leading edge point O1 or the aerodynamic center O2 shown in the figure below? Since the aerodynamic center does not vary with the angle of attack, the pitching moment remains constant regardless of changes in the angle of attack. Therefore, if the reference point for the pitching moment coefficient is also located at the aerodynamic center, I believe the coefficient Cm should also be constant.

CM
CM746×392 47.4 KB

(3) Based on the local blade chord ci, the actual pitch axis PitchAxis position as mentioned in your post above, and the twist angle θi, I calculated the coordinate yi values of the local blade pitch axes. Are the yi values at the root, middle, and tip of the blade in the followiing figure correct?
I would appreciate it if you could provide 49 values of the local chord length ci of the blade on the basis of the above post.

yy
yy916×708 95.1 KB

Best regards,

35

Dear @Yangyang.Li,

Here are my responses:

  1. What is called the “blade coordinate system” in ElastoDyn is fixed in the root of the blade, with xb along the pitch axis and xb/yb oriented relative to the hub by the rigid-body blade-pitch angle. This is closest to what you call X1/Y1 on your left figure and X3/Z3 on your right figure, except that your figure on the left is misleading because for a rotor spinning clockwise around the shaft, the Y1 axis should be nominally directed toward the trailing edge, not the leading edge (your airfoil is flipped). What is called the “local blade coordinate system” in ElastoDyn is oriented with the “blade coordinate system” when the blade is undeflected, except that the structural twist is included to rotate xLb/yLb from xb/yb about zb; and when deflected, the “local blade coordinate system” orients with the blade deflection as well.
  2. The notation used by AeroDyn is that the aerodynamic center locates the origin of the pitching moment coefficient, which is O2 in your figure.
  3. Again, your airfoil is shown backwards because yb should be nominally directed toward the trailing edge, in which case I agree with your equations other than the sign should be flipped (with each being negative) in value. Regardless, here are the corresponding Chord values (in meters):

Chord
3.50000
3.50000
3.52259
3.52259
3.75111
3.86546
3.97982
4.09417
4.20852
4.32299
4.43723
4.55158
4.64086
4.68892
4.67340
4.65583
4.62481
4.57361
4.47116
4.36886
4.26699
4.15773
4.03527
3.90889
3.78264
3.66106
3.54106
3.42106
3.30100
3.18106
3.06106
2.94106
2.82106
2.70100
2.58106
2.46106
2.34106
2.28086
2.21120
2.10670
2.05445
1.97222
1.84552
1.71856
1.57988
1.39430
1.20872
1.00951
0.87760

Best regards,

36

Dear @Jason.Jonkman
Thank you very much for your prompt responses and with your guidance, I flipped my airfoil. However, I still have some questions regarding the first two issues:

  1. I have drawn the “local blade coordinate system” in the blade midspan and root as shown in the figure below, and am I correct? I hope to be corrected if improper. Assume there is no deflection in the root of the blade.

    blc
    blc1130×350 31.4 KB

  2. Theoretically, should Cm be constant if referenced to the aerodynamic center?

37

Dear @Yangyang.Li,

I agree with your revised figures for the “local blade coordinate system”.

I would normally expect Cm to be relatively constant and close to zero (assume the aerodynamic center is close to 1/4 chord) for steady conditions at low angles of attack, but would not expect this in general for high angles of attack or under dynamic conditions.

Best regards,