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:
you have given the same code twice in the previous post, whether we have to edit the exiting code or insert below. And also what about AD14 , is it enough to mention as “AD” alone or is there any special reason behind mentioning it as “AD14”. kindly reply thank you!!!
hi xiao sun;
i am getting the following errors while compiling the FAST_library.dll in visual studio kindly help me to rectify these errors. buildlog.txt (17.9 KB)
1)there are two places that you need to modify.
2) “AD” is new subroutine for the AeroDyn, which incorporates the BeamDyn, if I remember correctly. “AD14” is the old routine.
3) For the complying error, try to recompile the register file.
hi Jason.Jonkman ,
I have successfully compiled FAST with Multitab flap control option. This is a active flap control.Now from where the airfoil data could be generated for the flap which is at 70% to 95% from the blade root for various flap angles(i.e. angle of attack of that span). In AirfoilPrep is it possible to generate the foil data of a particular span of flap for different angle of attack?? thank you!!
AirfoilPrep really only functions for a single airfoil. To create tables with multiple airfoils (or different flap settings for the same airfoil), you’ll have to process each airfoil in AirfoilPrep separately and merge the results into a single file.
Have you set the last line in your AeroDyn v14 input file to “User” to enable the user-specified use of multiple (non-Reynold’s-number dependent) airfoils?
I went through the whole discussion and it is quite informative. I’m working on ATEFlap(Adaptive trailing edge flap) aerodynamic model. In order to verify my model I need airfoil data with different flap angles. As per your discussion you have mentioned that it is possible to generate airfoil data with flap angles through Airfoil Prep. As per my research so far I have found that we can generate airfoil data with flap angles through Xfoil and CFD simulations. I have been trying to generate the airfoil data with flaps through Xfoil but I could not. Is there any source available which explains the process. Any kind of help is highly appreciated.
If you want to generate the airfoil data with XFOIL, you can download XFLR5 from 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.
Hello Xiao,
I have used the XFLR5 to generate the airfoil coefficients with flap. I have used the coordinates of the airfoil provided in the FAST 5MW wind turbine. For example I have loaded the DU21_A17 airfoil coordinates with Reynolds number = 0.75E6. I have not found anything else to change. I have generated the polar for zero flap angle(same as the normal polar already given by FAST for the airfoil DU21_A17). However, the output polar coefficients are different to the original polar available. I would like to know if the deviation is due to the limited inputs I have given (only Reynolds number) or the accuracy of the software itself is less?
I can’t comment on the XFLR5 tool, but you should be aware that the airfoil polars for the blades of the NREL 5-MW turbine in the FAST archive include the influence of 3D corrections, including corrections for rotational augmentation (stall delay) and deep-stall drag (Viterna). Please see Section 3 of the NREL 5-MW specifications report for more information: nrel.gov/docs/fy09osti/38060.pdf.
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, Mach number and Ncrit. Then adjust it with AirfoilPrep to account for 3D effects.
Finally compare with the provided reference data.
Hi xiao,
To generate airfoil data ,using Xflr5 i have designed a foil and flap angle as 1,2,3,4,5 degrees. Using the XY coordinates , i have substituted in airfoilprep.But there no much change in the output CL and CD values.please brief the steps to generate the airfoil data using these two softwares. For what the Xflr5 is used and for what the airfoilprep is used??? Kindly explain the steps!!
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: youtube.com/watch?v=IFCL8IJlYnI
For airfoilprep, it is a correction for 3D effects. The initially aerodynamic coefficients should be obtained from XFLR5. After you get the coefficient, you paste them into airfoilprep, do the interpolate for the angle of attack, correction for the 3D effects, etc. The first README file explains the procedure.
hi Xioa sir;
Everything is ok sir. But where to get the XY coordinates of the blades used in the NREL wind turbine and also how to check the flap action(ie) the airfoil switching in FAST-MATLAB interface. I have designed the airfoil for different flap angles -5 to 5 degrees,
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).
Hi xiao,
I am asking about the impact of the flap angle input in FAST outputs!!not while inputting the flap angle??? is there any way to display the switching of airfoil data based on the flap deflection outside ???
thank you xiao;
sir i have another query that , i have chosen number of foil as 10 If i try to use flap at 70% of radius of the blade then is it enough to use the xfoil designed data for last 3 airfoil file ?? i have attached the aerodyn input file with the data you have sent with flap -5,0 and 5 degree. is my ideology is correct??? xiao.txt (9.18 KB) Test001_AD.txt (2.55 KB)