PURPOSE:
PROFILE is a utility for manipulating and/or displaying the
coordinates and other properties of airfoils. It processes
one or more profiles at a time in various ways (one way per
run). The input and output profiles may be in one of four
formats described below (basically as separate surfaces, as
a wrap-around surface, or in three-column form).
If plotting of the airfoil geometry is requested, all of
the profiles in the input dataset will be plotted on the
same pair of axes unless the "THREED" option is selected.
The plots can be of the original input data, or data
derived by PROFILE, or both. Curvature distributions may
also be plotted as may the optional pressure distributions.
Plotting of the airfoil geometries, curvature distributions
or pressure distributions is handled by a separate program,
QPLOT, which should accompany PROFILE. Users' guides are
available for PROFILE and QPLOT.
The four main choices for manipulating input profiles are
to REDISTRIBUTE the abscissas using conventional splines or
parametric splines depending on whether leading or trailing
edges are rounded; to MODIFY or perturb the ordinates in
some way according to shape functions added interactively;
to REFINE the ordinates by manipulating the curvature (act-
ually 2nd derivative) distribution while seeking or retain-
ing some maximum thickness value; and to OPTIMIZE one surf-
ace of one airfoil automatically, using a predetermined set
of shape functions with some of their parameters variable,
and a target curvature distribution to be matched in the
least squares sense.
Lesser options permit the user to RECTIFY profiles which do
not have the point common to the two surfaces in the usual
place, and to NORMALIZE or DENORMALIZE profiles. TRANSFORM-
ing between upper/lower surface representation and camber/
thickness representation (either way) is provided for, with
decambering as an option. Applying twist is available from
the ROTATE option.
Two options involve a "secondary" profile (prompted for at
a lower level): an option to COMBINE profiles (one of which
may be boundary layer displacement thickness); and an op-
tion to LOFT linearly between two profiles.
A "nose-job" option permits ROUNDing or SHARPENing of the
leading edge region - operations which have been made as
reversible as possible. More generally, the SMOOTH option
smooths the entire airfoil (or just one surface) by fitting
combinations of "Wagner" functions, which are also employed
by the OPTIMIZE and MODIFY options, or by implicit and/or
explicit smoothing (possibly weighted nonuniformly).
Tabulation of coordinates along with derivatives and curva-
ture is provided, as well as saving the manipulated profile
as a new output file.
Saving of y" distributions is also an option, for possible
editing and reuse in REFINE mode.
Spreadsheet-compatible output of all likely tabular quanti-
ties is also provided for the simpler operating modes. This
requires the two surfaces to have common abscissas.
NOTES:
PROFILE has evolved considerably since its inception as a
basic redistribute-and/or-plot program. Provision for arbi-
trary perturbations to the input geometry, with tabulation
of the resultant coordinates and derivatives, required some
reorganization, but the structure should now serve for most
likely purposes. Some implementation considerations follow.
* The case of a 2-element airfoil forced the decision to plot
all input profiles on the same page (although the "THREED"
option has since been introduced). Normalization of such
combinations proved an awkward option to provide. The user
should use the normalization option carefully. Normaliz-
ation of 3-D wings is not available.
* The multiple-profile case also prevented plotting of more
than one frame type (such as curvature distributions in ad-
dition to the airfoils) - hence the saving of separate
files for later plotting.
* Large-scale plots are feasible (with optional windowing),
but exact scaling cannot be guaranteed because of the vari-
ability of the output devices available. (Plots of the
same data on the same device can vary slightly from plot to
plot.)
* Derivatives and curvature values are normally estimated by
finite differences for consistency with REFINE and OPTIMIZE
modes. It is well known that these approximations can be
poor in the presence of very small X increments and limited
precision in the Ys.
* An option to plot the full wrap-around curvature distribu-
tion using parametric spline derivatives has been provided
for a proper look at the leading edge region. But the .ypp
file of 2nd derivatives is suppressed in this case to avoid
inappropriate use with the REFINE mode.
* For simplicity, each of the MODIFY, REFINE, and OPTIMIZE
options assumes that the coordinates have been normalized.
METHOD:
The basic steps are as follows:
* Prompt for mode of operation and the input profile file name.
* Set defaults for user inputs and use an input control file
to override some of them if necessary.
* Scan all of the input profiles, for scaling and normalizing
purposes. Use EOF to handle the unknown number of profiles.
* Rewind the file and process the (now known number of) profiles
one at a time, according to the selected mode.
* Write the following output files as requested:
Revised profile coordinates in one of 4 formats
Original and/or revised airfoil geometry for plotting
(a QPLOT file)
Tabulated coordinates with derivatives and curvatures
A more complete, spreadsheet-compatible file
Second derivatives for possible reuse by REFINE mode
Original and revised curvature data, including target
curvature data for OPTIMIZE mode (another QPLOT file)
Cps estimated for original and revised airfoil (QPLOT
format)
MODES OF OPERATION:
MODE 0: "Display" mode - no modifications involved. Gen-
erate requested output files, which could include
saving the coordinates in a different format. MODE
<=3 is required for spreadsheet-compatible output.
MODE 1: Rearrange or rectify the geometry data so that the
common leading-edge point is indeed the one with
minimum abscissa and shift ordinates by an input
input amount if required. Only the revised pro-
file may be tabulated/plotted in this case. A ver-
tical shift option is also provided.
MODE 2: Normalize profile(s) according to the total range
of x or by input chord & leading edge coordinates.
A negative chord value will denormalize. The same
input values are used for each element of a multi-
element airfoil.
MODE 3: Redistribute the abscissas and derive correspond-
ing ordinates. Conventional or parametric spline
techniques are used depending on whether the lead-
ing edge is sharp or rounded. Distributions along
the arc (in T rather than X) are an option. Menu:
-1 = Read new Xs (or Ts) from a file in standard
PROFILE format (though y coordinates may be
omitted if desired).
0 = Distribute points uniformly.
1 = Distribute points sinusoidally bunched near
the leading edge.
2 = Distribute points sinusoidally, near both
the leading and trailing edges.
3 = Sinusoidal bunching around an internal pt.
4 = Vinokur distribution (first, last increments
increments specirfied.
A prompt will also be issued for the number of
points to be generated on each surface.
MODE 4: Perturb geometry data according to user-selected
shape functions (interactive).
MODE 5: Refine the airfoil, typically modifying (or re-
taining) its thickness while retaining (or modify-
ing) its curvature distribution(s). Numerous user
inputs are prompted for in this case, since there
are several likely ways provided for manipulating
the curvature distributions. Defaults are provided
where possible. The 4 main choices:
(1) Leave a surface unchanged (while presumably
refining the other);
(2) Change the thickness with minimal changes to
the existing curvature (none of the follow-
ing constraints on the original y" values);
(3) Impose a constant-2nd-derivative constraint
in some single region (to remove a bump or a
spike in the curvature distribution, or per-
haps to modify regions of flatness by con-
straining second derivatives - and hence the
curvature - away from zero);
(4) Constrain the curvature via an input file of
2nd derivative values (possibly derived from
an earlier run of PROFILE, or prepared by
hand). The table does not have to cover the
whole abscissa range; linearly interpolating
table look-ups are used.
Brief descriptions of the inputs prompted for in
"refine" mode follow:
* Desired % thickness: <CR> retains present thickness.
* Width param. for y: Affects the nonuniform scaling
applied to the ordinates (both
surfaces). The default is 2.0. Larger (3.0-4.0)
tends to retain leading/trailing edge shape more
while 1.0 would constrain fore and aft less.
* Input y" table: <CR> means there is none, else
the file name is entered. This
file should be in the standard "PROFILE" format.
It can cover any range of abscissas. (Linear
interpolation is used.) It may be an edited
version of the file from a previous run of
PROFILE, or it may be much cruder. The 2nd deriv-
ative values entered act as constraints on the
curvature since curvature and y" are related if y'
is not large.
* Constant y" value: <CR> means no such constraint -
retain existing curvature values
as much as possible. Otherwise, a value of y"
entered will be sought in the abscissa range that
is prompted for next.
* Corresp. x range: Enter low and high x values on
the same line. Allow for the
fact that strict inequalities are used when the
program tests for being within this range. E.g.:
Enter .39 .61 or .39,.61 if you intend for the
constraint to apply in [0.4,0.6].
* Width param. for y": Default is 3.0. Affects non-
uniform weighting of the equa-
tions representing 2nd derivative constraints in
the overdetermined system being solved. Since the
actual values of the 2nd derivatives being sought
also act in a weighting sense, effects of this
variable are not easy to predict. Values of 2.0 or
1.0 should tend to let y" change more.
* x for peak y" weight: The absolute values of Y" are
so much bigger than those of Y
that they all need to be scaled down in the system
being solved. If you are trying to flatten the
curvature plot in some region, pick the center of
the region for this input. Otherwise, use the mid-
chord value.
* y" weights, x/c=0,1: Default is 0.004. See next item.
* peak y" weight: Default is 0.04. These provide
for the fact that the absolute
values of y" are typically smaller in the mid-
section than near the leading/trailing edges, so
they should be weighted more, especially in view
of the fact that any y" constraints applied are
typically in the mid-section. See above.
MODE 6: Optimize one surface of one profile using a pre-
determined set of shape functions, some parameters
of which are automatically varied so as to achieve
a curvature distribution matching some target cur-
vatures in the least squares sense.
MODE 7: Transform representation of profile(s) between
upper/lower surface and camber/thickness (either
way - the user is prompted for the direction). An
option to decamber a section is also provided.
MODE 8: Rotate a profile about some point to apply twist.
MODE 9: Combine primary profile with a secondary profile
(read from a separate file). This was prompted by
a need to add or remove a boundary layer displace-
ment thickness (positive by definition) but has
been arranged to handle true addition/subtraction
of distinct profiles as well.
MODE 10: Loft between primary and secondary profiles.
MODE 11: Nose-job option: Round or sharpen the leading edge
region via splines.
MODE 12: Smooth either surface or both surfaces using least
squares techniques (linear combination of n Wagner
functions plus a "ramp" for thick trailing edges),
or by implicit and/or explicit methods involving a
(possibly nonuniform) weighting of y".
GEOMETRY INPUT:
Standard PROFILE format is shown below. The lower surface
is optional, but a zero must be read for NL if no lower
surface is included unless this is the last airfoil in the
file (meaning EOF can be used to indicate NL=0). In this
case, a symmetrical airfoil is assumed.
TITLE <CHARACTER*80>
NU Upper surface <Integer # pts., first token>
X Y <Reals, first two tokens>
X Y :
: : : (May be X/C, Y/C;
: : : Xs are increasing)
: : :
NL Lower surface <Integer, first token> <may be 0>
X Y <Reals, first two tokens>
X Y :
X Y ! Trailing comments are permitted
: : :
: : : (Xs are increasing)
: : :
! X Y <Pt. suppressed; NL must be adjusted>
: : :
: : :
NOTE: For standard format, if both surfaces are present, PROFILE
expects them to have the same leading edge point. The trailing
edge points may differ.
The next two formats are wrap-around clockwise and wrap-around
counterclockwise, where the coordinates begin at the trailing
edge, wrap around the leading edge, and end at the trailing edge.
The clockwise case begins with the lower surface, and the counter-
clockwise case begins with the upper surface. The format shown
below is essentially the same for both cases. NPTS is the total
number of points on the airfoil.
TITLE <CHARACTER*80>
NPTS <Integer, first token>
X Y <Reals, first two tokens>
X Y :
: : : (May be X/C, Y/C;
: : : Xs are decreasing
: : : until the leading
: : : edge, then increasing)
NOTE: Wrap-around formats do NOT have duplicate leading edge points.
The fourth format is three-column format. The airfoil has
the same abscissas for both surfaces in the 1st column and
ordinates for the upper and lower surfaces in the 2nd and 3rd
columns respectively. Abscissas are increasing as with standard
format. Here NPTS is the number of points on either surface.
TITLE <CHARACTER*80>
NPTS <Integer, first token>
X YU YL <Reals, first 3 tokens>
X YU YL :
: : : : (May be X/C, Y/C;
: : : : Xs are increasing)
: : : :
: : : :
CONTROL INPUTS:
A file containing keyword inputs and values may be used to
override default options. In general, the keywords refer to
the airfoil plot file and other output options, and apply
to all modes. Prompts are issued for inputs needed by a
particular mode.
KEYWORD GUIDELINES AND DEFINITIONS:
Keyword/value pairs may appear with more than one pair on a
line. However, the multivalued keywords PLTLINE, CPSLINE,
CRVLINE, and NOFILE must not appear with other keywords on
the same line.
The default value in each case appears in square brackets.
KEYWORD VALUES and synonyms DESCRIPTION
------- ------------------- -----------
FORMAT [SAME] One of four formats for output profile.
PROFILE or STANDARD May be in standard PROFILE format (ab-
CLOCKWISE or WRAPAROUND scissas increasing), clockwise wrap-around
COUNTERCLOCKWISE format, counterclockwise wrap-around for-
THREE-COLUMN or mat, or 3-column format. SAME means the
THREE_COLUMN or same format as the input profile. NOTE:
THREECOLUMN or To allow easily for several synonyms for
TABLE for the THREE-COLUMN value, only the first
5 characters of the value are checked.
PLTLINE [DEFAULT] Controls line types of curves on profile
LINE plots. One value may be included for
DASH each curve on the plot. The default is
DOT symbols connected by a solid line, with
CHAINDASH a different symbol type for each succes-
CHAINDOT sive curve. The first curve typically
THICK represents the original profile; the
SYMBOLS second curve represents the revised one.
Overriding the default might be desirable
when plotting multi-element airfoils or
when lines without symbols are required.
At most 20 curves are provided for. Note:
All the line types in QPLOT are available.
SYMBOLS refers to symbols with no line
connecting them.
CPSLINE [see PLTLINE above] Controls line types on Cps plots in the
same manner as PLTLINE above. One value
per curve may be included, chosen from
the same list of values as those shown
for PLTLINE.
CRVLINE [see PLTLINE above] Controls line types on curvature plots
in the same way as PLTLINE and CPSLINE.
CURVATURE or [NONPARAMETRIC] or CURVATURE and DERIVATIVES are synonymous
DERIVATIVES [FINITE_DIFFERENCE] controls for the type of calculations
SPLINE or used for derivatives and hence curvature.
PARAMETRIC or The default is separate-surface treatment
WRAPAROUND using finite differences, as needed for
consistency with PROFILE's REFINE and
OPTIMIZE options. The two surfaces appear
as separate frames in the curvature plot.
Otherwise, the full wrap-around curvature
distribution is calculated using a para-
metric spline and plotted on one frame.
The default normally suffices unless the
region of interest is very near a rounded
leading edge. Note that not all of the
possibilities are provided for, such as
parametric finite differences.
MINCURVATURE [-5.] Cutoff values for plotted curvatures.
MAXCURVATURE [+5.] Practice shows that +/-5. give useful
plot scaling by ignoring the high curv-
ature values near the leading edge. On
the other hand, it may well be desired
to focus on the leading edge region. Set
both to 999. to obtain the full range.
See the CURVATURE/DERIVATIVES control.
NOFILE [NONE] Used to suppress any combination of the
DAT seven output files generated by PROFILE.
PLT The values correspond to the extensions
TAB of the file names. See elsewhere for a
CRV complete description of file contents.
YPP NONE serves only to assist leaving the
CPS NOFILE control word in the input file
SPREAD even if all outputs are desired.
PLOT [BOTH] Controls plotting of original OR revised
ORIGINAL profile. The default is to plot both
REVISED original and revised (if one exists).
PRECISION [FULL] Controls number of digits in output
ENGINEERING airfoil coordinates. FULL gives F11.8
if possible, or E15.8 if any X >=10.
ENGINEERING gives the traditional F10.6
common to many flow solvers.
THREED [FALSE] or [NO] For plotting of multiple stations from
TRUE or YES a 3-D wing. The default is the 2-D case.
XAXIS [6.4] Length of x-axis in inches. The default
is normally appropriate for an 8.5 x 11
page in portrait mode.
The following four keywords apply to windowing. Any or none
of them may be used.
XMIN [minima and Minimum abscissa for desired window
XMAX maxima of Maximum abscissa for desired window
YMIN the input Minimum ordinate for desired window
YMAX coordinates] Maximum ordinate for desired window
SAMPLE CONTROL FILE:
A sample input file follows. Note that keywords and values
may be separated with blanks, commas, colons, equals signs,
pr tabs. Remember, keywords with more than one value should
appear on separate lines. Any keyword or text value may be
truncated to unambiguous leading characters. Blank lines
and trailing ! comments are ignored.
FORMAT = STANDARD PRECISION = FULL
PLOT BOTH THREED:NO
PLTLINE = SOLID, SOLID
CPSLINE = DOT, SYMBOLS
CRVLINE = SOLID, DASH, CHAINDOT
XAXIS = 20.
XMIN = 0. XMAX 0.1
MAXCURVATURE = 999. ! Both 999. means plot the full
MINCURVATURE = 999. ! curvature range
DERIVATIVES = PARAMETRIC
NOFILE: YPP SPREAD
OUTPUT FILES:
The following seven output files are generated by PROFILE.
Any of the files may be suppressed using the keyword
NOFILE. The user is prompted for an identifier, which will
become the first part of each file name. File extensions
are fixed.
<identifier>.DAT Contains airfoil coordinates that have been re-
vised in some way. May be in one of four formats;
default is the same format as input coordinates.
<identifier>.PLT Contains airfoil geometry coordinates and other
information necessary for later QPLOTing. May be
a plot of original profile, revised profile, or
both. (Default is both, superimposed.)
<identifier>.TAB Contains tabulated coordinates, first and second
derivatives and curvatures for the original and
revised profile (if a revised profile exists).
Other diagnostics may be written here, including
a record of selected shape functions from the
MODIFY option.
<identifier>.CRV Contains curvatures of the original and revised
profiles (if a revised profile exists) for later
QPLOTing. Also to be used as the basis of target
curvature data when OPTIMIZE option is used. The
MAXCURVATURE and MINCURVATURE keywords determine
the plot axis range, but the full surfaces appear
in the file (except for the first and last pts.).
See the description of these keywords for how to
obtain a full wrap-around curvature distribution.
<identifier>.YPP Contains second derivatives in standard PROFILE
format, for possible reuse in "refine" mode.
When a profile has been revised, the file will
contain only the second derivatives of the
revised profile. Otherwise, the file will con-
tain only the second derivatives of the original
profile.
<identifier>.CPS Contains QPLOTable estimates of Cps for user-sup-
plied alpha and free stream Mach number (revised
and/or original).
<ident>.SPREAD Contains spreadsheet-compatible (tab-delimited)
tabular data. Available only if MODE <= 3, and
only if both surfaces have common abscissas.
ENVIRONMENT:
DEC VMS; SGI IRIX; Fortran 90
HISTORY:
Dec. '82 DAS/RAK Original design.
12/09/82 LJC Original coding (plot/redistribute data points).
04/29/83 LJC Added option to "rectify" input data points.
July '83 LJC Added a 3-D capability and an option for reading
a file of new abscissas in "redistribute" mode.
09/27/83 LJC Interactive MODIFY routine incorporated.
Oct. '83 DAS Integrated alternative version of MODIFY as the
REFINE option; provided for saving curvature and
y" values; removed REDISTRIB function from main.
11/09/83 LJC Added de-normalizing to normalizing option; in-
cluded these as a separate MODE; reordered MODEs
in order of complexity.
01/20/84 DAS Incorporated OPTIMIZE mode.
04/12/84 DAS Took advantage of QPLOT's new legend capability.
July '84 LJC Added reading and writing of wraparound formats.
07/24/84 LJC Added calculation of thickness for all modes.
Aug. '84 LJC Changed from namelist to keyword inputs.
09/14/84 LJC Changed legend entry to be read from dataset and
added prompt for title. Formerly, the title was
read from dataset and the legend was hard-coded.
Oct. '84 LJC Arranged for all plotting to be done outside of
PROFILE using QPLOT. Formerly, much of the
program was devoted to plotting the airfoil
geometry with DISSPLA.
Dec. '84 DAS Incorporated cheap estimates of Cp distributions
using algorithm supplied by Ilan Kroo of the RAC
Branch at NASA Ames. Added Cl, Cm calculation.
01/24/85 LJC Allowed for original and revised plots with MODE
= 3. Also modified to take advantage of QPLOT's
new equal axis scaling option.
02/12/84 DAS Added TRANSFORM option.
02/13/85 LJC Added shifting of ordinates to RECTIFY mode.
02/19/85 DAS Fixed REDISTRIB to handle rounded trailing edges
properly; took out "BLUNT" input parameter.
02/28/85 LJC Added 3-column format to PRREAD and PRWRIT.
03/22/85 LJC Allowed for absent input control file (meaning
an empty file is not needed). Also added two new
keywords to RDKEYS for controlling line types on
Cps and curvature plots.
06/17/85 DAS Provided generalized distributions in REDISTRIB,
via GETDIS/DSTRIB in place of XGRID.
09/05/85 DAS Fixed minor error in QPLOTable airfoil data file.
09/30/85 DAS Added COMBINE option.
10/09/85 DAS Suppressed plot windowing control values from
QPLOTable file if they are not in use.
10/21/85 DAS Introduced LSTFIL to echo the input control file
to the .TAB file for future reference.
11/04/85 DAS Mixup with END CURVE/END FRAME for OPTIMIZE mode
target curvatures crept in (how? used to be OK).
12/30/85 DAS Added ROUND option (tentatively).
04/24/86 DAS Cp at leading edge was wrong.
08/11/86 DAS Added SMOOTH option (fitting of Wagner functions
in linear least squares sense).
09/24/86 DAS AFGEOM in place of CALCTHICK in main program;
menu options by name now, as well as by number.
10/20/86 RAK AFGEOM returns CAMBER and THICK as fractions; must
convert to % chord at calling level.
02/11/87 DAS Functionality of BOUNDS changed somewhat.
03/11/87 DAS Made use of PROTECT utility (prompted by duplicate
point case that dies ungracefully otherwise).
04/24/87 DAS Menu items clarified and made more unique (because
of SELECT's option for choosing by name or number).
Greater precision in output coordinates now by default.
Also: traps bad IDENT now (more than one token is
presumed to be a goof).
04/27/87 DAS Introduced PRECISION argument in PRWRIT.
08/31/87 DAS Trailing edge angle added as AFGEOM output.
09/23/87 DAS If MODE=0 but PRECISION is not the default, assume
that a revised airfoil dataset is required.
04/29/88 DAS Added spreadsheet-compatible output file.
12/01/88 DAS Turned on spreadsheet file for MODE <= 3 now.
11/29/89 DAS/RGL Plots for multi-section 3D cases w/ blank subtitle from
the initial prompt now use the case titles as subtitles.
'Original' suppressed from headers if 'Revised' does not
apply.
02/14/90 DAS Installed OPENER in 9 places. File names are now in
lower case to indulge the Unix community.
03/13/90 " Raised MXPTS from 201 to 300.
06/28/90 " Added the LOFT option.
06/29/90 " Added the ROTATE option.
04/22/91 " Indicated "current axes" for thickness/camber printout.
10/22/91 " Replaced the ROUND option with the "nose-job" option
(round or sharpen). Providing for reversing the
operation can mean letting through a non-rectified
airfoil.
10/24/91 " Provided for full wrap-around curvature plot (parametric
derivatives). Adjusted the tabulations accordingly.
Added the control scheme description above (adapted from
RDKEYS) and the geometry data description (adapted from
PRREAD).
01/07/95 " Original chord and leading edge are now tabulated;
"normalize" mode *.crv file had mismatched X min/max.
06/13/95 " Output of the *.ypp file is now as advertised above.
11/21/95 " TRANSFORM mode now has an option to decamber a section.
12/19/96 " Added SINF and four "COS" shape functions.
12/20/96 " Extended SMOOTH option to allow y"-based implicit and/or
explicit smoothing as an alternative to Wagner fitting.
10/20/99 " Fortran 90 upgrade, mainly to eliminate use of '0' for
carriage control.
AUTHORS:
Leslie Collins, David Saunders, Sterling Software/NASA Ames, Mt. View, CA
ACKNOWLEDGMENTS:
Robert Kennelly (ex-Sterling, now NASA Ames) provided the inspiration and
many key ideas.
The Aerodynamics Division at NASA Ames funded this software under contract
to Sterling Software (previously known as Informatics, Inc.).
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