How do I upload data points for NACA airfoil into simflow to run cfd simulation?

Question

I have a text file filled with points that consist of x, y, and z coordinates of a NACA airfoil. I want to ultimately run a cfd simulation over the wing at different angles of attack using software called simflow. How do I import this data into the software so I can run my simulation?

Answer 1

I'm assuming that your data is delimited and doesn't contain any headers e.g.

1.002 -0.001 -0.002
0.986  0.246  0.234
.
.
1.200  0.897  0.672

Assuming you are on a UNIX or UNIX-like system with Python installed, save the following piece of code as a new file called 'convert_to_obj.py'. This script converts an airfoil .dat file into an '.OBJ' file which can be manually imported into SimFlow before meshing.

#!/usr/bin/env python
'''
Script to convert a NACA airfoil in the Selig format into an OBJ file
which can be read by SimFlow.
'''
# Make sure that your airfoil .dat file has the '.dat' extension!!!!

# Argument parser from the command line
import argparse

parser = argparse.ArgumentParser( description='Script to convert a NACA'
                                  'airfoil in the Selig format into an'
                                  ' OBJ file that can be read by SimFlow')

parser.add_argument('files', type=str,
                    help='Choose files to convert, specify path.'
                    ' Enclose entire path in single-quotes')


args = parser.parse_args()

# Import and convert file
import glob
AllFiles = glob.glob( args.files)

for datfile in AllFiles:

    InFileID = open( datfile, 'r')

    # If you have header files in the .dat file, specify the number of
    # header lines below. (for Selig, numheader = 1)
    numheader = 0
    for i in range(numheader):
        InFileID.readline()

    # Slurp all the remaining lines of the .dat file and close it
    DataLines = InFileID.readlines()
    InFileID.close()

    # Open a new file to write to (change extension)
    OutFileID = open( datfile[:-4] + '.OBJ', 'w')

    # Write the name of the group (in our case, its just 'Airfoil')
    OutFileID.write('g Airfoil\n')

    for line in DataLines:
        OutFileID.write('v ' + line )

    OutFileID.close()

# This should create an .OBJ file that can be imported into SimFlow.

To run this script do (from the terminal/command line)

$ python convert_to_obj.py './relative/path/to/airfoil.dat'

Or you can convert a bunch of files at a time

$ python convert_to_obj.py './relative/path/to/airfoil*.dat'

Note that the above script will create vertices. I'm also a bit confused as to why your airfoil has 3 coordinates. Airfoils are two-dimensional. This script will work for 3d data, but will only create vertices.