.: code Airfoil Smooth

Applies smoothing to airfoil profile coordinates provided in the input file fn.dat.
In version 2.0 added ability to correct smoothing strip interactively.
In version 3.0 added ability to choice the boundary conditions for the spline airfoil geometry.
Smoothing range should be defined in order to perform smoothing. It can be defined in the input file individually for each point of the geometry, or alternatively define global parameter "specified smooth strip" that applies constant range to all points. Before smoothing the foil geometry is transformed to a chord=1 with a zero angle of rotation. The new improved geometry is stored in the output file fn.out in three formats. Detailed geometrical parameters of airfoil shape calculated before and after smoothing are stored as well.

The graphical user interface is based on MS VisualBasic.
Use "." as decimal separator on Windows platforms.

.: formats of input file:

  • Format 1 (X YU YL DU DL) - In this format, coordinates of the airfoil geometry are specified from leading to trailing edge for both surfaces.

    1. X - x-coordinate of airfoil geometry
    2. YU - y-coordinate of upper surface
    3. YL - y-coordinate of lower surface
    4. DU - smoothing range for upper surface
    5. DL - smoothing range for lower surface

  • Format 2 (X Y D) - In this format, the coordinates are given in the following order: trailing edge, upper surface, leading edge, lower surface, trailing edge

    1. X - x-coordinate
    2. Y - y-coordinate
    3. D - smoothing range

  • Format 3 BLWF - In this format, upper surface coordinates are specified from leading to trailing edge first, then lower surface coordinates follow in the same order.

    1. NU - number of points on upper surface
    2. NL - number of points on lower surface
    3. XU - x-coordinate of upper surface
    4. YU - y-coordinate of upper surface
    5. XL - x-coordinate of lower surface
    6. YL - y-coordinate of lower surface
    7. D - smoothing range
In all formats, the second line (marked in red in the examples) must be exactly as shown in the examples.

.: panel Input file:

Input File the name of input file
Output file the name of output file
Chord length Airfoil chord length
Max Smooth Strip maximum smoothing range
The kind of input geometry format of input file
Transformation without rotation rotation lock
1-st der. first derivative on the spline boundaries
2-nd der. second derivative on the spline boundaries
new X-grid new X-grid
Output STL format Output file in STL format

.: foil geometry:

x0 x-coordinate of leading edge
y0 y-coordinate of leading edge
chord airfoil chord
thick maximum thickness
x_thick x-coordinate of maximum thickness
eps angle of rotation
trail angle of trailing edge
slopt tangent of the camber line slope at trailing edge
mu number of coordinates on upper surface
ml number of coordinates on lower surface

.: thickness and camber:

T(x) =0.5(Yв-Yн) - thickness
C(x) =0.5(Yв+Yн) - camber

.: curvature (top window), smooth strip (bottom window):

K(t) radius of curvature of airfoil surface
t =sqrt(x) - for upper surface
t =-sqrt(x) - for lower surface
D(I) the smoothing range in position I
I the left ScrollBar changes position I
D the right ScrollBar changes smoothing range in position I

.: the region of the leading edge:

Y(t) y - coordinates in vicinity of leading edge
t =sqrt(x) - for upper surface
t =-sqrt(x) - for lower surface

.:Cp distribution:

Mach Mach number
Alpha angle of attack
C lift lift coefficient

.: Examples of input data file formats:

Format 1

airfoil data: test1
(X YU YL DU DL)
0.000000.00000 0.00000.000 0.000
.2 .035 -.035 0.01 0.01
.5 .06 -.06 0.01 0.01
.8 .02 -.02 0.01 0.01
1.00000.001 -.001 0.000 0.000

Format 2

airfoil data: test2
(X Y D)
1.00000.00000 0.000
.8 -.02 0.01
.5 -.06 0.01
.2 -.035 0.01
.00000.00000 0.000
.2 .035 0.01
.5 .06 0.01
.8 .02 0.01
1.00000.001 0.000

Format 3

airfoil: RAE2822
BLWF
YSYM NU NL
0.00000 17.00000 17.00000
XSING YSING TRAIL SLOPT
0.0250.00000 10.345-0.125
XU YU D
0.000000 0.000000 0.000
0.005 0.017608 0.0001
0.0125 0.026723 0.0001
0.05 0.045757 0.0001
0.1 0.057471 0.0001
0.15 0.064844 0.0001
0.20 0.069794 0.0001
0.30 0.074746 0.0001
0.40 0.074853 0.0001
0.50 0.071141 0.0001
0.60 0.064045 0.0001
0.70 0.053598 0.0001
0.80 0.039522 0.0001
0.90 0.021540 0.0001
0.95 0.011391 0.0001
0.97 0.007432 0.0001
1.000000 0.000935 0.000
XL YL D
0.000000 0.000000 0.000
0.005 -0.016411 0.0001
0.0125-0.024802 0.0001
0.05 -0.043695 0.0001
0.1 -0.056273 0.0001
0.15 -0.064417 0.0001
0.20 -0.069838 0.0001
0.30 -0.074585 0.0001
0.40 -0.073142 0.0001
0.50 -0.065941 0.0001
0.60 -0.052969 0.0001
0.70 -0.035236 0.0001
0.80 -0.016055 0.0001
0.90 -0.002637 0.0001
0.95 -0.000166 0.0001
0.97 -0.000047 0.0001
1.000000 -0.000935 0.000

.: Format of file: X_INP.DAT:

XU 32
0.000000
0.001000
0.002000
0.003000
0.005000
0.007500
0.010000
0.020000
0.030000
0.050000
0.075000
0.100000
0.150000
0.200000
0.250000
0.300000
0.350000
0.400000
0.450000
0.500000
0.550000
0.600000
0.650000
0.700000
0.750000
0.800000
0.850000
0.900000
0.950000
0.970000
0.990000
1.000000