Search found 36 matches

by Xiao.Sun
Wed Sep 21, 2016 9:18 am
Forum: Rotor Aerodynamics
Topic: Movable trailing edge flaps implementation
Replies: 45
Views: 18794

Re: Movable trailing edge flaps implementation

You can export the aerodyn data of the blade-flap section.
In aerodyn input file, switch NOPRINT to PRINT.
by Xiao.Sun
Wed Sep 21, 2016 8:45 am
Forum: Rotor Aerodynamics
Topic: Movable trailing edge flaps implementation
Replies: 45
Views: 18794

Re: Movable trailing edge flaps implementation

Hello Srinvasa,

I suppose you are designing a feedback control scheme.
In order to check the flap angle, what I did is to add a scope module before I feed the flap angle signal back to the FAST module .
(To find it, you can search scope in Simulink library).

Best,
Xiao
by Xiao.Sun
Thu Sep 15, 2016 8:27 am
Forum: Rotor Aerodynamics
Topic: Movable trailing edge flaps implementation
Replies: 45
Views: 18794

Re: Movable trailing edge flaps implementation

Hello Srinvasa, For the XFLR5, you design the airfoil with flap by defining the profile coordinates. Then you perform a XFOIL direct analysis by changing the angle of attack, you will get a series of aerodynamic coefficients, which are purely 2D. Here is an example for XFLR5 analysis: https://www.yo...
by Xiao.Sun
Mon Sep 12, 2016 12:12 pm
Forum: Structural Analysis
Topic: Natural frequency of NREL DS monotower in OC3.
Replies: 34
Views: 21400

Re: Natural frequency of NREL DS monotower in OC3.

Dear Dr. Jonkman

Thank you for your help.
I see what was wrong with my results.


Best regards,
Xiao
by Xiao.Sun
Mon Sep 12, 2016 11:30 am
Forum: Structural Analysis
Topic: Natural frequency of NREL DS monotower in OC3.
Replies: 34
Views: 21400

Re: Natural frequency of NREL DS monotower in OC3.

Dear Dr. Jonkman, Thanks for your comment. I should have explained it more clearly. These three figures show the comparison of the bending mode shape between original blade and blade with flap. I expected the mode shape is correct since the paper also plot a similar mode shape for a similar rotating...
by Xiao.Sun
Fri Sep 09, 2016 6:04 pm
Forum: Structural Analysis
Topic: Natural frequency of NREL DS monotower in OC3.
Replies: 34
Views: 21400

Re: Natural frequency of NREL DS monotower in OC3.

Hi, Jason, The flaps cover 30% of the blade from the tip. Although it only increases the total blade mass by 5%, the local sectional mass is increased by 40%. This significantly changes the mode shape of the blade (estimated by Bmodes ). I test the setting with the original 5MW turbine. Both lineari...
by Xiao.Sun
Fri Sep 09, 2016 3:08 pm
Forum: Structural Analysis
Topic: Natural frequency of NREL DS monotower in OC3.
Replies: 34
Views: 21400

Re: Natural frequency of NREL DS monotower in OC3.

Dear Jason, I performed both linearization study and my OMA study on the original 5MW wind turbine and the turbine with trailing edge flap. I assume the flap only increase the mass of the blade and does not change the stiffness of blade. From both studies, I found the 1st rotor flap modes are reduce...
by Xiao.Sun
Fri Sep 09, 2016 8:41 am
Forum: Rotor Aerodynamics
Topic: Movable trailing edge flaps implementation
Replies: 45
Views: 18794

Re: Movable trailing edge flaps implementation

Dear Majjari, The XFOIL is based on the planar flow theory if I remember correctly. The accuracy is limited. For a more accurate estimation, I would use CFD. It is also good to start with a clean airfoil to calibrate your flow simulation model. For XFLR5, you can play with different Reynolds number,...
by Xiao.Sun
Thu Sep 08, 2016 9:10 am
Forum: Rotor Aerodynamics
Topic: Movable trailing edge flaps implementation
Replies: 45
Views: 18794

Re: Movable trailing edge flaps implementation

Hello Majjari,

If you want to generate the airfoil data with XFOIL, you can download XFLR5 from http://www.xflr5.com/xflr5.htm.
It is a GUI based on XFOIL. The theory is the same but it is relatively easy to use.
The software contains a manual and it is quite self-explanatory.

Thanks.
Xiao
by Xiao.Sun
Tue Sep 06, 2016 12:08 pm
Forum: Structural Analysis
Topic: Natural frequency of NREL DS monotower in OC3.
Replies: 34
Views: 21400

Re: Natural frequency of NREL DS monotower in OC3.

OK, I see. I conducted a linearization analysis. And the damping of the generator (around 0.1Hz) is approaching infinite.
by Xiao.Sun
Tue Sep 06, 2016 11:35 am
Forum: Structural Analysis
Topic: Natural frequency of NREL DS monotower in OC3.
Replies: 34
Views: 21400

Re: Natural frequency of NREL DS monotower in OC3.

Hello Jason,

Thanks for the explanation.

The figure was obtained at mean wind speed of 16 m/s. The two stable modes were also found for 12 m/s but not for 8 m/s and 4 m/s. Thus, I think it is related to the drivetrain response to pitch controller. But why the damping is so large?
by Xiao.Sun
Sun Sep 04, 2016 11:45 am
Forum: Structural Analysis
Topic: Natural frequency of NREL DS monotower in OC3.
Replies: 34
Views: 21400

Re: Natural frequency of NREL DS monotower in OC3.

Hello Dr. Jonkman, I am using the stochastic subspace identification method (with Multiblade coordinates transformation and harmonic removal method) to study the modal parameters of the 5MW wind turbine in a onshore configuration. This is the stabilization diagram that I obtained from analyzing the ...
by Xiao.Sun
Mon Jul 25, 2016 11:40 am
Forum: Rotor Aerodynamics
Topic: Movable trailing edge flaps implementation
Replies: 45
Views: 18794

Re: Movable trailing edge flaps implementation

hi Xiao.Sun; i am trying the alter the source code as per your instructions. The doubt is in FAST_subs.f90 file in how many place should we insert the code: " IF ( p_FAST%CompAero == Module_AD14 ) THEN !Xiao Sun: add m_FAST CALL AD14_InputSolve_NoIfW( p_FAST, m_FAST, AD14%Input(1), ED%Output(1...
by Xiao.Sun
Fri Jun 24, 2016 9:18 am
Forum: Rotor Aerodynamics
Topic: Movable trailing edge flaps implementation
Replies: 45
Views: 18794

Re: Movable trailing edge flaps implementation

Hello, I did this work one year ago. So I may forget some modifications I did. Currently, since no one describe this process, I plan to detail it in the appendix of my PhD thesis. You can read it and cite it, but it will be published in this August. I also did some microtab control in my research pr...
by Xiao.Sun
Thu Jun 23, 2016 8:35 am
Forum: Rotor Aerodynamics
Topic: Movable trailing edge flaps implementation
Replies: 45
Views: 18794

Re: Movable trailing edge flaps implementation

Hello,

No, it is not enough. You have to modify several other subroutines according to your applications. Then recomply the FAST lib file in order to run with Simulink.

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