Download JAVAFOIL User's Guide Contents

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*.txt
multi-element airfoil geometry in form of simple x-y coordinate sets arranged in two
columns. The elements of multi-element airfoils must be separated by a pair of xand y-values each having a value of 999.0 or larger.
*.xml
multi-element airfoil geometry in JAVAFOIL’s hierarchically structured xml format.
*.png, *.gif, *.bmp, *.jpg
single element airfoil geometry from an image file. For details, see next section.
Note that JAVAFOIL selects the input file format according to the file name extension.
Importing scanned images
You can also load an airfoil from a bitmap image in GIF, PNG, BMP or JPG format.
JAVAFOIL then tries to find an airfoil shape in this image by comparing the image points with
the color found in the upper left corner of the image. Therefore the image should have no
border, and a monochrome background. Before scanning the image, a smoothing filter is
applied to remove spurious points from the image. To achieve acceptable results an image
width of 1000 or more pixels is recommended. The interior of the airfoil shape can be empty
or arbitrarily filled, because the algorithm searches from the top and bottom edges of the
image and stops when it detects the border of the shape. The resulting points are filtered again
to improve the smoothness of the shape. Nevertheless the results will not be perfect, but this
method can be considered as a last resort to quickly determine airfoil coordinates if only a
scanned image is available. It is recommended to inspect the resulting velocity distribution
and to use the inverse design method for smoothing the airfoil shape.
Figure 2: Airfoil image (top) and comparison of the original (dashed) and the reconstructed airfoil shape
(solid) using JAVAFOIL’s bitmap import capability on the Geometry card.
JAVAFOIL’S Geometry Generators
Note on NACA airfoils
The construction of the cambered NACA airfoil sections requires that the thickness
distribution is erected at right angles to the camber line. Some computer programs do not
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