Open ckesanapalli opened 5 years ago
maidmentdaniel
commented
5 years ago I get a bunch of nan's too. I'm not sure why.
from xfoil import XFoil
from xfoil.test import naca0012
xf = XFoil()
xf.airfoil = naca0012
xf.Re = 1e6
xf.max_iter = 40
a, cl, cd, cm, co = xf.aseq(-20, 20, 0.5)returns:
ajwahab
commented
5 years ago Encountering the same on macOS 10.14.3. Noticed that the max thickness, chord, LE, and TE values differ from those given in README.md.
What I get:
>>> xf.airfoil = naca0012
Number of input coordinate points: 160
Clockwise ordering
Max thickness = 0.000000 at x = 0.000
Max camber = 0.000000 at x = 0.000
LE x,y = -0.06001 -0.06001 | Chord = 0.08487
TE x,y = 0.00000 0.00000 |What the README.md indicates I should be getting:
>>> xf.airfoil = naca0012
Number of input coordinate points: 160
Counterclockwise ordering
Max thickness = 0.120008 at x = 0.308
Max camber = 0.000000 at x = 0.033
LE x,y = -0.00000 0.00000 | Chord = 1.00000
TE x,y = 1.00000 0.00000 |Seeing that the thickness, among other values, is computed from the airfoil coordinates, perhaps there is an issue with how the naca0012 coordinate array in test.py is being parsed by the fortran routines?
Seems to work just fine on Ubuntu 18.04, though aseq now also outputs 5 values (minimum pressure coefficient co was recently added in [4354e485d979b318b8d583bca0720d32697c61a4]), so README.md should be updated to:
>>> a, cl, cd, cm, co = xf.aseq(-20, 20, 0.5)This project is fantastic!
ckesanapalli
commented
5 years ago @ninfinity How did you install xfoil module it in ubuntu. I am trying to install in ubuntu but I am getting a bunch of errors.
ajwahab
commented
5 years ago Try my fork of the project. I’ve submitted a pull request that includes a minor edit that lowers the minimum cmake version requirement to 3.10, which seems to be the current default in Ubuntu 18.04.
ckesanapalli
commented
5 years ago @ninfinity : can you give me instructions on how to install your version. I am trying but I am getting error.
home/chaitu1351/anaconda3/lib/python3.7/distutils/dist.py:274: UserWarning: Unknown distribution option: 'zip_save'
warnings.warn(msg)
error: can't copy 'build/lib.linux-x86_64-3.7/xfoil/xfoil.cpython-37m-x86_64-linux-gnu.so': doesn't exist or not a regular file
['-DCMAKE_BUILD_TYPE=Release', '-DCMAKE_LIBRARY_OUTPUT_DIRECTORY_RELEASE=/home/chaitu1351/src/xfoil/build/lib.linux-x86_64-3.7/xfoil', '-DCMAKE_ARCHIVE_OUTPUT_DIRECTORY_RELEASE=build/temp.linux-x86_64-3.7', '-DPYTHON_EXECUTABLE=/home/chaitu1351/anaconda3/bin/python']
Nick-Zhang1996
commented
5 years ago @maidmentdaniel @ckesanapalli @ninfinity The problem you're having is resulted from an improper call to self._lib.get_airfoil() in xfoil.py. Somehow the memory buffer used for x and y are entangled and the function gets same array for x and y. If you check xf.airfoil you'll see xf.airfoil.x is actually set to the values of xf.airfoil.y. I suspect this is a bug with ctypes library, and by changing platform I believe @ninfinity switched to a different version of ctypes, which fixed the problem. I have a fix in my fork of this library and I have absolutely no idea why it works. If you come across this issue, my version may help you.
wzc001
commented
3 years ago Excuse me,I also encountered this problem(NAN). Have you solved it?
ckesanapalli
commented
3 years ago Nope.
I tried to run the demo code in the ReadMe file, but for the command
But for the following command,
a, cl, cd, cm, co = xf.aseq(0, 1, 0.5)I got the output as
The values are
print(a, cl, cd, cm, co)May I know how to resolve this issue
@daniel-de-vries: Your python code is really great and looks really apt for my project. I would really appreciate if you could help me resolving this issue.