AFSMO

A simple Python Wrapper for NASA AFSMO program [TM-84666]. Original AFSMO source code was downloaded from PDAS.

Special thanks goes for Prof. Michael Selig for providing the AFSMO program and helping out in countless ways throughout.

Installation

pip install numpy matplotlib argparse scipy

AFSMO fortran source code can be compiled in Unix systems easily using gfortran, and using a free Intel Fortran compiler in Windows

gfortran -w afsmo.f -o afsmo
ifort afsmo.f

Data/Process Flow

The below diagam outlines the dataflow through the program. Blue highlighed functions take place through afsmo.py

afsmo.out contains complete log of the smoothing operation. useful in case if someone tries to understand what caused a failure or an error.

afsmo.pch contains the punch file. as outlined in the TM-84666, and help text, what goes into the pch file can be controlled by --ipunch switch.

afsmo.smr contains smoothed original cordinates along with first and second derivate data.

afsmo.dat contains interpolated airfoil cordinates. this file is used as a side-effect if someone prefers AFSMO built in interpolation scheme. python wrapper changes this file inplace as a standard dat file for ease of use.

Usage

D:\AFSMO>python afsmo.py -h
usage: afsmo.py [-h] [-d] [-i] [-n] [-p] [-a] [--max-iter] [--ipunch] [--icamtk] [--ibad] [--itrn]

A simple wrapper for NASA AFSMO airfoil smoothing program

optional arguments:
  -h, --help         show this help message and exit
  -d , --dat-file    Input *.dat file name
  -i, --interpolate  Dat file with (n) interpolated x coordinates will be generated when set
                     Default => True
  -n , --n-inter     Number of cosine spaced points to be interpolated
                     Default =>  160
  -p, --plotter      Plots the original and Smoothed airfoils
                     Default => True
  -a, --aspect       Uses real aspect ratio for plotting
                     Default => True

Advanced options:
  --max-iter         Maximum Number Of Smoothing Iterations
                             Default =>80
  --ipunch           Ipunch - Punch Output Option
                         0 - No Punched Output
                         1 - Smoothed (X,Y,W) Punched
                         2 - Smoothed (Theta,Y/C,W) Punched
                         3 - Smoothed (Theta,Yps,W) Punched
                             (Ylte, Ynose, And Yute Also Punched)
                         4 - Smoothed (Theta,Ypps,W) Punched
                             (Ylte, Ynose, And Yute Also Punched)
                         5 - Thickness And Camber Distribution
                             (X/C, Y/C, T/C/2, And Slope) Punched
                         6 - Interpolated Coordinates Punched
                             Default => 1

  --icamtk           Icamtk - Thickness And Camber Distribution Option
                         0 - Do Not Compute Thickness And Camber
                         1 - Compute Thickness And Camber
                             Default => 1

  --ibad             Ibad - Bad Coordinate Check Option
                         0 - Do Not Check For Bad Coordinates
                         1 - Check For Bad Coordinates
                             Default => 1

  --itrn             Itrn - Input Coordinate Translation And Rotation Option
                         0 - Do Not Translate And Rotate
                         1 - Translate And Rotate So That X-Axis
                             Corresponds To The Longest Chordline
                             Default => 1

Few Examples

Bare minimum

python afsmo.py -d goe602.dat

Here R140.dat is a standard XFoil format *dat file. Python script will read this file and generate *in file that can be fed in to original AFSMO program, runs it and extracts the values from AFSMO logs and spits out a *dat file which can directly be loaded in to XFoil. The smoothed *dat file is named as **_sm.dat.

With Plots [Most General use-case]

In addition to the minimal example shown above, plotting can be enabled with -p flag. -i or --interpolate flag is used to generate an output *dat file with interpolated list of cosine spaced x cordinates specified by the -n option.

python afsmo.py -paid goe602.dat
python afsmo.py -paid goe602.dat -n 360

With Plots but without unit aspect ratio

python afsmo.py -pid goe602.dat

With airfoil de-rotation (True by Default)

python afsmo.py -pid goe602.dat --itrn 0
python afsmo.py -pid goe602.dat --itrn 1

Without plots

 python afsmo.py -id goe602.dat

Above could be useful to run in batch mode.

Contributing

Pull requests, bug reports or any suggestions for improvements are welcome.

License

MIT