HYPER_AERO Description:
-----------------------
Calculate Newtonian-type aerodynamic lift/drag/moment coefficients for
a hypersonic vehicle at a range of Mach numbers and angles of attack.
A choice of impact pressure methods and shadow methods is provided.
The geometry OML (outer mold line) is input either as a triangulated
surface in FAST or STL formats, or as a surface paneling of the form
produced by AEROSURF (structured multiblock surface grid in PLOT3D/FAST
format). If the OML is in surface patch form, it is triangulated here
prior to the aerodynamic calculations.
Coefficients for one or more flight conditions are calculated and
tabulated as standard output. A surface Cp distribution is an optional
output, corresponding to the last case calculated. The associated
triangulation may be suppressed (since it may have been produced by
an earlier run), and does NOT match the initial triangulation. This
is because the Cp values are associated with the triangle centroids,
not their vertices. Rather than interpolating to the vertices, each
Cp is simply written three times and the corresponding triangulation
contains all the implied repetitions of points with trivial connectivity.
Special case for Cp studies:
--------------------- ------
If a single triangle is being analyzed (two faces), and the Cp file
name is not 'none', that file is used for saving (M, Alpha, Cp, Cp-shadow)
at all of the indicated angles of attack (= impact angles), where the
range 0 : 180 degrees is suggested.
Here is a sample such single triangle with two faces:
3 2 0 ! points, faces, tetrahedra
-.5773502693 -.5773502693 1.154700539 ! X coordinates
0. 0. 0. ! Y coordinates
-1. 1. 0. ! Z coordinates
1 3 2 1 2 3 ! Connectivity
1 1 ! Component numbers
Sample control file (standard input):
-------------------------------------
INPUT SURFACE QUADS/TRIS/STL? NORMAL_FLAGS? FORMATTED?
sharp-v5.xyz quads .TRUE. .TRUE.
OUTPUT TABULATION OUTPUT TRIANGULATION Cp file (last case)
sharp-v5.coefs none mach20.cps
REF. LENGTH REF. AREA X_CG Y_CG Z_CG GAMMA
39.7534 173.95 20.862 0. 0. 1.2
MACH1 MACH2 INCREMENT
20. 20. 1.
ALPHA1 ALPHA2 INCREMENT
0. 10. 2.
BETA1 BETA2 INCREMENT
0. 0. 1.
PITCH/YAW/ROLL MOMENT SWITCHES (to overcome convention uncertainties)
-1. 1. 1.
X/Y/Z CONVENTION SWITCHES (for conversion to Jameson convention)
1 0 0
0 1 0
0 0 1
IMPACT METHOD SHADOW METHOD
1 1
Notes:
------
1. The internal X/Y/Z convention is that of the Jameson flow solvers:
X points downstream; Y points up; Z points outboard (left wing).
The permutation inputs allow for switching the sign of X and for
swapping and/or switching the signs of Y and Z (only).
Output coordinates are transformed back to the input convention
if necessary.
2. NORMAL_FLAGS applies to structured surface patches only.
If NORMAL_FLAGS is TRUE, the surface paneling file should end with the
following data (as from the AEROSURF program):
Components:
1 1 1 1 2 2 2 ... (as many integers as surface patches)
Signs to apply to normals:
-1 -1 -1 -1 1 1 1 ... (means for switching the sign of normals)
Otherwise, all component numbers are set to 1, and all signs to +1,
meaning the input paneling should have outward normals implied by the
right-hand (i,j,k) rule: k should be out of the surface.
3. The (final case) Cp distribution will not be written if the file
name is 'none' or 'NONE'. The file is formatted (ASCII text).
It contains 3 * NFACES values - the same Cp at each vertex of each
triangle, for all triangles. See above for the special case of a
single triangle, where instead Mach, Alpha, Cp, Cp-shadow are saved.
4. Likewise, the corresponding triangulation will not be saved on disk if
the specified file name is 'none' or .NONE'. Otherwise, the file is
formatted (not binary), for FAST. It contains all vertices of every
triangle (meaning replicated points) in order to match the Cp file.
A Tecplottable form of this file is also written now.
5. STL triangulation format:
solid ABC
facet normal 1. 0. 0.
outer loop
vertex 50. 30. 10.
vertex 50. 30. -10.
vertex 50. 31. -5.
endloop
endfacet
facet normal ...
::::::::::::
endfact
::::::::::::::
::::::::::::::
endsolid ABC
6. Available impact pressure methods:
1 Modified Newtonian
2 Improved Tangent-Cone
3 Tangent-Wedge (Empirical)
4 Tangent-Wedge (Oblique shock relationships of NACA TR 1135)
5 Newtonian + Prandtl-Meyer expansion method (slope matched)
6 Inclined Circular Cone
7 Dahlem-Buck method
8 Free Molecular Flow
7. Available shadow methods:
1. Cp = 0.
2. Prandtl-Meyer expansion from free stream
3. Newtonian + Prandtl-Meyer
4. Base pressure relationship
History:
--------
10/18/00 D.A.Saunders Program NEWTONIAN is an initial completion of
James Reuthers beginnings for AEROSURF-type
paneled surfaces, with potentially reusable
utilities in argument-driven form.
10/20/00 " The surface normals are problematic. Ideally,
the input paneling should be such that they are
outward normals. If not, a switch can now be
imposed by this program (see NORMAL_FLAGS).
10/24/00 " Added L/D output and second tabulation for
more convenient plotting of polars.
11/29/00 " Store the surface Cp distribution, and write it
and/or the triangulation to disk if specified.
Thanks to Scott Thomas (Raytheon/Ames) for the
suggestion that avoids interpolation.
12/13/00 " FACE_AREA(*), not PROJECTED_AREA(1:3,*), is now
stored at the cost of one multiply per triangle.
01/03/01 " Added option to read a triangulated surface.
02/02/01 " Provided X/Y/Z convention switches.
Arranged for choice of impact pressure method
(all components and all flight conditions for
now, but this needs generalizing), prompted by
installation of a free molecular flow method.
02/08/01 " Installed improved tangent-cone method from HABP.
02/12/01 " Installed tangent-wedge empirical method (HABP).
02/14/01 " Installed tangent-wedge method COMPR from HABP.
03/01/01 " Installed Newtonian + Prandtl-Meyer method of
NEWTPM from HABP. (COMPR never really needs it.)
03/02/01 " Installed INCLINED_CONE method (ACONE in HABP).
03/05/01 " Installed Dahlem-Buck method from in HABP.
The ACONE method is not right yet.
03/16/01 " Introduced shadow method options in TANGENT_WEDGE_
EMPIRICAL (only).
03/23/01 " Put the impact and shadow methods inside the
loop over surface elements, as opposed to
replicating the loop for each impact method.
04/06/01 " Introduced STL triangulated geometry input option.
04/23/01 DAS/JJR NEWTONIAN program name has changed to HYPER_AERO.
07/05/01 DAS Arranged for saving (M, Alpha, Cp, Cp-shadow) for
the special case of a single triangle.
06/07/02 " Handled zero increments for ranges of Mach and
Alpha; trapped likely misuse of NORMAL_FLAGS.
07/19/02 " STL input had a bug.
04/01/08 " The outputs in FAST format are no longer useful,
but writing an addition file in Tecplot format is
easier than eliminating them. The file name is
fixed at Tecplotable_Cp.dat.
09/15/10 " The control file is now read from standard input
instead of being hardcoded as hyper_aero.inp.
Any coordinate transformation is applied to the
CG coordinates as well, and is undone before any
surface Cp distributions are written.
Authors: David Saunders (ELORET Corporation), James Reuther (ASA Branch).
Sponsor: Reacting Flow Environments Branch, NASA Ames Research Center, CA
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