Dear All,
To better investigate a 13.2MW two-bladed downwind turbine, I wanted to go from AeroDyn v14.05 to AeroDyn v15.03 (both with FASTv8) since there are more output sensors available in the latter. To do so, I changed the AeroDyn Input File of v14.05 (SUMR-13i_v6_AD14.ip) with the new one for v15.03 (SUMR-13i_v6_AD) and also created the new AeroDyn v15.03 Blade Definition Input File (FASTBlade_precomp_v6_s4.dat). All the values used in both .ipt files are based on a Blade Input File that was prepared for FASTv7 for the same turbine (FASTv7_Blade_Definition.dat). Due to some definition differences between the modules, I interpolated and extrapolated some points to have a refined blade shape and also to define the tip and root sections of the blade properly. Other than that, I used the following formulas that are taken from another discussion in the forum ([url]Definition of parameters] - Jun 14, 2017) to complete AeroDyn v15.03 Blade Definition Input File;
BlCrvAC = -(0.25-AeroCent)ChordSIN(AeroTwst)
BlSwpAC = -(0.25-AeroCent)ChordCOS(AeroTwst)
BlTwist = AeroTwst
Furthermore, PitchAxis values in ElastoDyn Blade Definition Input File (EDFASTBlade_precomp_v6_s4.dat) are calculated with the formula PitchAxis = 0.5 - AeroCent taken from README_FAST8.pdf (pg.41).
As I mentioned before, I ran FASTv8 with both AeroDyn v14.05 and v15.03. Other than the AeroDyn input files mentioned above, everything is kept constant for those test runs and All DOFs were disabled to have rigid conditions. For the comparison of the results, the blade section at 84.05m from the blade root is selected and sensors at that section are enabled for both versions.
I have a couple of questions regarding the results;
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What could be the reason for the differences between the two runs, and especially for aerodynamic power, is it normal to have a 4% difference in it while there is not that much of a difference between other aerodynamic parameters shown in the figures?
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The parameter used in Cp calculation ‘RtVAvgxh’ according to the formula specified in another discussion in the forum ([url]Pitch rate in Fast v7] - Feb 24, 2017) fluctuates while everything is supposed to be rigid. What could be the reason for those fluctuations? Furthermore, the wind is steady and its horizontal speed is set to 11.3m/s. Shouldn’t those fluctuations occur around 11.3m/s instead of 11.19m/s even if those fluctuations have to be there?
Sorry for the long post and thank you for your help in advance.
Best regards,
Emin Camadan
Note: Since the folder size is too big to upload here I shared a dropbox link for you to view the files.
[url]Dropbox - SUMR-13i (AD14 vs AD15) - Simplify your life
