Inquiry About IEA Task 29 Mexnext Aeroelastic Code Availability

Wind & Water Structural Analysis
1

Hello,
I hope this message finds you well. I would like to use the wind tunnel test data provided in the technical report for IEA Task 29 Mexnext. However, I have been unable to locate the aeroelastic code for this model. Is it open-source? If so, could you please provide me with the GitHub link or direct me to where I can access it?

Best regards,
Dereje

2

Dear @Dereje.Haile,

Can you clarify what you are asking for?

For the Mexnext wind tunnel data, I would ask Gerard Schepers of TNO.

For the aeroelastic code, Iā€™m not sure what you are asking about.

Best regards,

3

I want simulation results from the MEXICO wind tunnel test, including:

  1. The MEXICO power coefficient and axial force coefficient.
  2. The MEXICO flapwise fatigue-equivalent blade root bending moment at different yaw angles.
  3. The MEXICO normal force variation as a function of azimuth angle.

I want to conduct a simulation for the NREL 5MW wind turbine, but I am unsure if I can compare the NREL 5MW wind turbine model simulation results with the MEXICO wind tunnel test data.

Q1: By setting the same tip speed ratio for my model, can I use the NREL 5MW wind turbine model simulation results to validate them against the MEXICO wind tunnel measurements?

Best regards,
Dereje

4

Dear @Dereje.Haile,

The NREL 5-MW baseline wind turbine is not the same turbine as used in the MEXICO wind tunnel tests (even when considering consistent scaling in rotor size), so, ā€œnoā€, you wouldnā€™t be able to reasonably compare the results between the two.

For the MEXICO data, I would ask Gerard Schepers of TNO.

Best regards,

5

Thank you for the clarification. Which wind turbine model results should I use to validate against the MEXICO wind tunnel tests?

Best regards,

6

Dear @Dereje.Haile,

I was not involved in the MEXICO phase of IEA Wind Task 29 (MexNext) and donā€™t have an OpenFAST model of that turbine to share. There could be an OpenFAST model that has been developed of this turbine by someone, but Iā€™m not sure who would have it. Again, this is probably a better question for Gerard Schepers. If you have the properties of this turbine, you could also put together the OpenFAST model yourself.

Best regards,

7

I will ask Prof. Gerard Schepers. Thank you!

Best regards,
Dereje

8

Dear Jason,

I have asked Prof. Gerard Schepers for the OpenFAST model but havenā€™t received a reply yet. Although I couldnā€™t obtain the detailed properties of the tower (mass, stiffness, size), blade (mass, stiffness, size), or the nacelle (size and mass), the airfoil families utilized along the turbine blade span have been provided. They are as follows:

  • DU 91-W2-250 at the root of the blade;
  • RISƘ A1-21 at mid-span;
  • NACA 64-418 at the outer part of the blade.

I have a few questions about this:

  1. Could these airfoils (DU 91-W2-250, RISƘ A1-21, NACA 64-418) provide the same aerodynamic drag and lift force as those used in the NREL 5 MW wind turbine blade?

Best regards,

9

Dear @Dereje.Haile,

These airfoils all differ a bit from the airfoils used in the NREL 5-MW baseline wind turbine, so, the airfoil data will differ as well. Besides, the airfoil data provided with the FAST / OpenFAST models of the NREL 5-MW baseline wind turbine include corrections for 3D rotational augmentation (stall delay) that is only valid for a given rotor.

Best regards,

1 Like
10

Thank you very much!

Best regards,

11

Dear Jason,

I have a few question on Standalone AeroDyn output symbols

  1. Regarding the AeroDyn output symbols BĪ±NĪ²Fx, BĪ±NĪ²Fy, BĪ±NĪ²Fn, and BĪ±NĪ²Ft, Iā€™m unable to use them directly in the AeroDyn output section. How to properly implement them?
  2. What is the correct symbol for the blade root flapwise moment in standalone AeroDyn?

Best regards,
Dereje

12

Dear @Dereje.Haile,

Regarding (1), you should replace BĪ± with the blade number, i.e., B1, B2, or B3 for blades 1, 2 or 3 and you should replace NĪ² with the output node number, i.e., N1, N2, ā€¦ up to N9 (assuming NBlOuts = 9. Node N1 corresponds to the 1st node entered in the BlOutNd list, node N2 corresponds to the 2nd node in the list, etc., up to NBlOuts output nodes.

Regarding (2), the total integrated aerodynamic load along the blade expressed in the blade-root coordinate system for blade BĪ± are AeroDyn outputs BĪ±AeroFx, BĪ±AeroFy BĪ±AeroFz for the forces, and BĪ±AeroMx, BĪ±AeroMy, BĪ±AeroMz for the moments.

Best regards,

13

Dear Jason,
Thank you for your detailed information. I have set tangential and normal forces according to the these explanation and that solves the issue. However, the simulation cases are getting aborted for blade-root loads out put channels, i.e,

"B1AeroFx, B1AeroFy,B1AeroFz" 
"B1AeroMx, B1AeroMy,B1AeroMz".
  1. What could be the problem causing these cases to get aborted?

Best regards,
Dereje

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14

Dear @Dereje.Haile,

It looks like you are using a quite old version of the standalone AeroDyn driver; these blade-root aerodynamic outputs were added more recently. Youā€™ll have to upgrade to use these outputs.

Best regards,

15

Dear Jason,

Thank you for your time and guidance. The results I obtained for tangential force (Ft) and normal force (Fn) using an older version of standalone AeroDyn are comparable to the experimental results from the MEXICO model. I would like to continue using this older version of AeroDyn. Could you please clarify the following:

  1. In the older version, are the equivalent outputs for the forces BĪ±AeroFx, BĪ±AeroFy, and BĪ±AeroFz represented as RtAeroFxh, RtAeroFyh, and RtAeroFzh, respectively?
  2. Similarly, are the moments BĪ±AeroMx, BĪ±AeroMy, and BĪ±AeroMz equivalent to RtAeroMxh, RtAeroMyh, and RtAeroMzh?

Iā€™d appreciate your confirmation or any corrections if Iā€™ve misunderstood the mapping between these outputs.

Best regards,

Dereje

16

Dear @Dereje.Haile,

The integrated loads on a single blade were added to AeroDynā€™s OutList only recently. AeroDyn outputs RtAeroFxh, etc. are the total integrated loads across the entire rotor.

Best regards,

1 Like
17

Thank you very much! I will switch to the latest version AeroDyn.

Best regards,
Dereje

18

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Dear Jason, My research subject is the IEA 15 MW wind turbine, and I am currently attempting to understand the calculation process of the turbineā€™s thrust. As shown in the figure, this is the wind turbine thrust and total blade aerodynamic force (B1AeroFx+B2AeroFx+B3AeroFx) that I calculated using OpenFAST. As you can see, at a wind speed of 10 m/s, the mean values of these two parameters differ by 17.60%. Then I reviewed the relevant documents and codes. My understanding is that the latter is the data in the blade coordinate system. Therefore, converting it to the hub coordinate system might require considering the buoyancy of the hub. Could you please give me your opinion on my understanding? If you could offer some suggestions or references to assist me in understanding the calculation process of thrust, I would be extremely grateful. Best regards, Lei Xue

19

Dear @Lei.Xue,

The thrust offset you are seeing is not the result of buoyancy (which is important for under-water turbines, but negligible for a wind turbine), but the result of the weight and inertia included in the ElastoDyn output RotThrust, which are not accounted for in AeroDynā€™s output B1AeroFx, etc.. See my post dated Feb 27, 2020 in the following forum topic for my answer to a similar question for additional discussion on this thrust offset: NREL 5-MW reference turbine - CP, CQ, CT Coefficients.

Best regards,