AFLR2 Example Cases
Data files for several AFLR2 sample cases are provided. Package archives
with all of the example cases are provided in aflr2-examples.tar.gz
(tar-gzip archive for Linux/MacOSX)
and aflr2-examples.zip
(zip archive for Windows). Copy the package archive files and unpackage them in
a location of your choosing to run the example cases. All cases require minimal
resources. The input surface edge grid files provided for the sample cases are
ASCII formatted files of BEDGE type. In the following case examples the output
mesh file is an ASCII formatted 2D UGRID type file. Alternative file types can
be used. By default the output volume mesh is an ASCII formatted 2D UGRID type
file named case_name.ugrid.
An isotropic element planar mesh can be generated for any of the sample cases
using the following command.
aflr2 case_name
See the AFLR2 documentation
for information on available options and usage. Alternatively, you can view
text-based documentation at the command line with the following command.
aflr2 -help
The XPLT2 program is provided to visualize the mesh that is output
from AFLR2. To display the output mesh using XPLT2 use
the following command.
xplt2 case_name.ugrid
Text-based documentation is available at the command line with the following
command.
xplt2 -help
Several AFLR2 example cases are provided and described below.
Mesh between two circles.
aflr2 circle
Quad mesh between two circles.
aflr2 -quad circle
3D mesh between two cylinders. The volume mesh contains 11 planes
with a spacing of 2 between each. A 3D mesh visualization system is required to
display the mesh.
aflr2 -3d 11 2 circle
Mesh around NACA0012 airfoil.
aflr2 n12
Mesh around NACA0012 airfoil with quad/trias.
aflr2 -quad n12
Mesh around NACA0012 airfoil with quads and h-refinement.
aflr2 -quad -href 1 n12
Mesh around NACA0012 airfoil with boundary-layer and wake. Note that the
initial normal spacing is set at the end of the BEDGE file. Note
that n12.fsurf file was created by another code.
aflr2 -fixed_surfaces -bl n12
Mesh around NACA0012 airfoil with boundary-layer and wake and with BL quads.
Note that the initial normal spacing is set at the end of the BEDGE file. Note
that n12.fsurf file was created by another code.
aflr2 -fixed_surfaces -bl -quadbl n12
Mesh around NACA0012 airfoil with boundary-layer and wake. This
illustrates the differences between using fixed_surfaces
and fixed_points. Note that the initial normal
spacing is set at the end of the BEDGE file. Note that n12.fpoin file was
created by another code.
aflr2 -fixed_points -bl n12
Mesh in a box showing different ways to treat the boundary-layer regions.
Note that the initial normal spacing is set at the end of the BEDGE file. Also,
note that boundary refinement is turned off to prevent refinement at the inlet
and outlet.
aflr2 -bl -bref 0 plate
Solution adapted mesh. Note that ramp.psrc
file was created by another code from a previous solution.
aflr2 -adapt ramp
Mesh in a box with adaptation sources. Note that box.psrc
file was created manually. The results show unrefined areas where refinement is
desired. This is due to the large change in element sizing specified and a more
realistic adaptation would have a more gradual evolution of the mesh and no
resulting under-refined areas.
aflr2 -adapt box
Mesh in a box with fixed points. Note that box.fpoin file was created manually. The fixed point file used is exactly the same as the adaptation
source file. In this case though the refinement is smooth an no unrefined
regions remain. This is due to the fact that fixed points are inserted into the
mesh at the start and not the end (as with adaptation sources). Typically fixed points are used to control spacing a priori.
aflr2 -fixed_points box
Mesh in a nozzle with BL quads. Note that the initial normal
spacing is set at the end of the BEDGE file. Also, note that boundary refinement is turned off to prevent
refinement at the inlet and outlet.
aflr2 -bl nozzle -bref 0 -quadbl
Axisymmetric 3D mesh in a nozzle with BL quads. Note that the initial
normal spacing is set at the end of the BEDGE file. Also,
note that boundary refinement is turned off to prevent refinement at the inlet
and outlet. The volume mesh contains 21 planes with a spacing of 4.5º between
each. A 3D mesh visualization system is required to display the mesh.
aflr2 -bl nozzle -bref 0 -quadbl -axisym 21 4.5
Mesh about a multi-element airfoil.
aflr2 m3
Mesh about a multi-element airfoil with boundary-layer and multiple wakes
and with BL quads. Note that the initial normal spacing is not set in the
BEDGE file. Note that m3.fsurf file was created by
another code.
aflr2 -fixed_surfaces -bl -blds 1.3e-5 -quadbl m3
Mesh with multiple different inner and outer shapes and with BL quads. Note
that the initial normal spacing is not set in the BEDGE file.
aflr2 -bl -blds 0.001 -quadbl shapes
Mesh for Atlantic ocean with field growth.
aflr2 -grow atlantic
Mesh for Atlantic ocean with field growth and
high-aspect ratio boundary quads. Note that the initial normal spacing is
not set in the BEDGE file.
aflr2 -grow -bl -blds 0.001 -quadbl atlantic
The BSURF2 program is also provided to generate boundary edge grid
files. It is an interactive program and the prompts should be descriptive
enough to allow usage. Package archives with example files for the BEDGE
code are provided in bsurf2-examples.tar.gz (tar-gzip archive for Linux/MacOSX)
and bsurf2-examples.zip
(zip archive for Windows). BSURF2 is not that well documented and it
would be much easier to use in a GUI. However, it gets the job done and is not
that painful to use. The objects in the geometry can be a circle, polygon, or
come from a data file. The data file must be a string of x and y coordinates
(one set per line) in sequential order that form a closed curve (do not
duplicate the last data point). The direction (clockwise or not) is not
important. A spline is generated for each object and automatically split at the
first and last data points and at detected discontinuities. Spline split points
can be added or deleted. A script file is created that allows one to rerun a
case with a corrected error or slightly different parameters. Edit the script
file (default name is bsurf2.script) to make changes and rerun BSURF2.
The # comments should provide information necessary to modify the right
parameters. If you make an error while running BSURF2 and want to start
over from a previous point in the session, then kill the process. In this case
edit the script file by deleting everything from the point you made the
unwanted step to the end of the file. Then rerun BSURF2 using the script file
you edited as the input script file. The program will redo all the steps
contained in the script file and return standard input control to you when it
reaches the end of the file. To run BSURF2 in interactive mode simply
enter the following and follow the interactive prompts.
bsurf2
Note that BSURF2 generates ASCII formatted type BEDGE edge grid files.
These are exactly the same as the older, and now obsolete, BSURF type files
that older versions of BSURF2 generated. AFLR2 can input BEDGE,
BSURF, 2D FGRID or 2D UGRID file types. See the UG_IO documentation for
a description of standard UG_IO file types used by AFLR2.
Several BSURF2 example cases are provided and described below. The script
files for each are configured to generate a suitable boundary edge grid for AFLR2.
Mesh around NACA0012 airfoil.
bsurf2 n12
aflr2 n12
Mesh in a box with BL quads.
bsurf2 plate
aflr2 -bl -bref 0 -blquad
plate
Mesh in a nozzle with BL quads.
bsurf2 nozzle
aflr2 -bl nozzle -bref 0 -quadbl
Mesh with multiple different inner and outer shapes.
bsurf2 shapes
aflr2 shapes