AFLR2 Option Details


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AFLR : ADVANCING-FRONT/LOCAL-RECONNECTION UNSTRUCTURED GRID GENERATOR
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AFLR2 is a stand-alone unstructured tria/quad element grid generation code.
It uses the Advancing-Front/Local-Reconnection (AFLR) procedure to generate a
tria/quad planar grid from an existing boundary edge discretization. Primary
input to the code is a boundary edge grid discretization. Input files, output
files, and option flags are described in the following Sections.
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aflr2 [-options] case

Option Flags
------------

-build or --build

List program version build number.

-version or --version

List program version number information.

-ver or --ver

List program version number.

-h

List summary of input parameters.

-help

List documentation of input parameters.

-melem value

 Set maximum number of elements to "value". The default value is 500000.

-min_out

 Turn off most all standard output except final total of points and elements.

-ibedge

 Read in a type BEDGE grid file. The default input grid file type is
 BEDGE. A BEDGE grid file contains a boundary surface definition created
 by bsurf2.exe or equivalent. Note that the BEDGE grid file is identical to the
 older named BSURF file. AFLR2 will read files named either *.bedge or *.bsurf.

-ifgrid

 Read in a type FGRID grid file. The default input grid file type is
 BEDGE. An input grid file contains a triangulated grid with boundary
 points and possibly field points.

-iugrid

 Read in a type UGRID grid file. The default input grid file type is
 BEDGE. An input grid file contains a triangulated grid with boundary
 points and possibly field points. No quad elements are allowed in the input
 grid.

-igrid

 Read in a type GRID grid file. The default input grid file type is
 BEDGE. An input grid file contains a triangulated grid with boundary
 points and possibly field points.

-fgrid

 Write out a type FGRID grid file. The default grid file type is UGRID.

-ugrid

 Write out a type UGRID grid file. If the output grid contains quad elements
 then the output grid file type is automatically set to type UGRID. The default
 grid file type is UGRID.

-grid

 Write out a type GRID grid file. The default grid file type is UGRID.

-axisym value1 value2

 Write out a 3D grid file for an axisymmetric geometry. The number of grid
 planes is specified by "value1". The default number of grid planes is
 2. The angle between grid planes is specified by "value2". The default
 angle is 10. If this option is selected then output grid file type will be
 automatically set to either a type FGRID or UGRID grid file. The default is 
 to write a 2D grid.

-3d value1 value2

 Write out a 3D grid file. The number of grid planes is specified by "value1".
 The default number of grid planes is 2. The distance between grid planes
 is specified by "value2". If the distance between grid planes is set to 0
 then aflr2 will set the distance to the minimum boundary edge grid spacing.
 The default distance is 0. If this option is selected then the output grid
 file type will be automatically set to either a type FGRID or UGRID grid
 file. The default is to write a 2D grid.

-ocase case
 Set case name for all output files to "ocase". The default is to set ocase
 to the input file case name "case".

-fixed_points

 Read in a set of fixed field points and add them to the initial triangulation.
 With this option an input case.fpoin file is required. This file contains
 the coordinates and desired spacing for each fixed field point. The default is
 not read in a set of fixed field points.

-fixed_surfaces

 Read in a set of fixed field surfaces and add them to the initial
 triangulation. With this option an input case.fsurf file is required. This
 file contains endpoint connectivity and grid boundary condition flag for each
 fixed field surface. It also contains coordinates and desired normal spacing
 for each point on the fixed field surface. The normal spacing is used only if
 -bl is selected and grid boundary condition flag for the particular fixed field
 surface is 1. The default is not read in a set of fixed field surfaces.

-keep_fixed_surfaces

 Keep fixed field surfaces within the grid and treat them as any other boundary
 surface. This option has no effect unless the -fixed_surfaces option is
 selected. The default is to remove fixed field surfaces.

-rm_fixed_surfaces

 Remove fixed field surfaces and merge the grid across each fixed field surface.
 The fixed field surface points are not modified only the connectivity is
 changed. This option has no effect unless the -fixed_surfaces option is
 selected. The default is to remove fixed field surfaces.

-adapt

 Read in a set of point sources and use them to refine the final grid. With this
 option an input case.psrc file is required. This file contains the
 coordinates and desired spacing for each point source. The default is not read
 in a set of point sources.

-cdfrs value

 Set the growth rate from adaptation sources to "value". The default value is
 1.1. This option has no effect unless -adapt is selected.

-cdfs0s value

 Set the no growth region around adaptation sources to "value". The default
 value is 2. This option has no effect unless -adapt is selected.

-quad

 Combine tria elements to form as many quad elements as possible within the
 quad element quality constrains. The default is to not form quad elements.
 Advancing-point point placement for right-angle isotropic elements is
 automatically used with the -quad option. If the -href option is used then the
 h-refined grid will contain only quads.

-quadbl

 Combine tria elements in the boundary-layer only to form as many quad elements
 as possible within the quad element quality constrains. The default is to not
 form quad elements. This option has no effect if the -bl option is not
 selected. If the -href option is used then the h-refined grid will contain
 refined quads and trias.

-bl

 Generate a boundary-layer grid. A boundary-layer grid will be generated from
 all surfaces with a grid boundary condition of 1. The grid boundary condition
 is set in the bedge file with the ibcibs array. The default is to not
 generate a boundary-layer grid. 

-blr value

 Set the boundary-layer normal growth ratio to "value". The default value is
 1.4. This option has no effect unless -bl is selected.

-blds value

 Set the initial boundary-layer normal spacing to "value". The default is to
 use the initial boundary-layer spacing specified in the input grid file. This
 option has no effect unless -bl is selected. 

-blf value

 Set the fraction of laminar boundary-layer thickness to "value". This is used
 along with the Reynolds number to determine the initial boundary-layer spacing.
 The default value is 0.01. The default is to use the initial boundary-layer
 spacing specified in the input grid file. This option has no effect unless -bl
 is selected. 

-y+ value

 Set y+ for a turbulent boundary-layer to "value". This is used along with the
 Reynolds number to determine the initial boundary-layer spacing. The default
 value is 2.  The default is to use the initial boundary-layer spacing
 specified in the input grid file. This option has no effect unless -bl is
 selected.
 
-Re value

 Set the reference Reynolds number per unit grid dimension to "value". This is
 used to determine the initial boundary-layer normal spacing when -y+ or -blf
 are selected. The default value is 1e+06. The default is to use the initial
 boundary-layer spacing specified in the input grid file. This option has no
 effect unless -bl and either -blf or -y+ are selected.

-grow

 Use specified growth from surfaces to determine isotropic spacing in the field.
 The default is to use linear interpolation. This option uses the boundary
 condition flag. The grid boundary condition is set in the bedge file with the
 ibcibs array. If the boundary condition flag is 0 and -grow option is selected
 then the spacing grows at a rate equal to cdfrb0. The spacing does not grow for
 a distance cdfs0b0 times the local spacing. If the boundary condition flag is 1
 and the -grow option is selected then the spacing grows at a rate equal to
 cdfrb1. The spacing does not grow for a distance cdfs0b1 times the local
 spacing.

-cdfrb0 value

 Set the growth rate from surfaces with a boundary condition flag of 0 to
 "value". The default value is 1. This option has no effect unless
 -grow is selected.

-cdfrb1 value

 Set the growth rate from surfaces with a boundary condition flag of 1 to 
 "value". The default value is 1.1. This option has no effect unless
 -grow is selected.

-cdfs0b0 value

 Set the no growth region for surfaces with a boundary condition flag of 0 to 
 "value". The default value is 3. This option has no effect unless
 -grow is selected.

-cdfs0b1 value

 Set the no growth region for surfaces with a boundary condition flag of 1 to
 "value". The default value is 3. This option has no effect unless
 -grow is selected.

-bref value

 Refine the boundary up to "value" times if adjacent boundaries are too close
 to each other. A value of zero will eliminate boundary refinement. The default
 value is 7.

-href value

 H-refine the grid "value" times. The default is 0.

-no_qm

 Do not generate grid quality output. The default is to generate grid quality
 output of element angle distributions.

-extra_qm

 Generate grid quality output which includes distributions of the element
 angles, element skewness, and maximum element edge length ratio. The default is
 to generate grid quality output which includes only element angle
 distributions.

-convert

 Convert file type and/or format of a previously generated grid file. With this
 option the grid will not be modified. Only the input grid options (-ibedge,
 -ifgrid, -iugrid) and the output grid options (-fgrid, -ugrid -axisym, -3d)
 will have any effect. All other options will be ignored. The default igrid
 file type is BEDGE. The default grid file type is UGRID.

-post

 Post process a previously generated field grid. With this option no new field
 points will be generated. Only the final grid quality smoothing,
 local-reconnection, quad formation, h-refinement (if any), and grid quality
 output generation will be performed. This option also automatically turns on
 the igrid file option (see -ifgrid -igrid -iplt -iquad -ispectrum) if it is not
 already selected. The default grid file type is UGRID. Note that the igrid
 file(s) will be written over by the output grid file(s).

-blrec

 Turn on all local-reconnection in BL region. The default is to limit
 local-reconnection in the BL region.

-advf

 Turn on advancing-front point placement The default is to use advancing-front
 point placement.

-advp

 Turn on advancing-point point placement The default is to use advancing-front
 point placement.

-circumcenter

 Turn on circumcenter point placement The default is to use advancing-front
 point placement.

-centroid

 Turn on centroid point placement The default is to use advancing-front
 point placement.

-edge

 Turn on advancement from satisfied edges. The default is to advance from
 satisfied elements.

-delaunay

 Turn on Delaunay local-reconnection. The default is to use min-max-angle.

-skewness

 Turn on min-skewness local-reconnection. The default is to use min-max-angle.

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 Additional option flags (generally not needed)
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-madv      (default=1)
-madvff    (default=1)
-madvpf    (default=0)
-mchkg     (default=1)
-melem00   (default=1)
-mrecm     (default=2)
-mrecmi    (default=2)
-mscb      (default=2)
-nbfr      (default=100)
-nblsmth   (default=20)
-nbrmadd   (default=3)
-nbsmth    (default=20)
-ngen      (default=10000)
-ngenbl    (default=10000)
-ngenbs    (default=10000)
-ngens     (default=10000)
-ninsmax   (default=100)
-nqual     (default=1)
-nqualq    (default=4)
-nsbmadd   (default=3)
-nsmth     (default=3)
-angbl1    (default=40)
-angbl2    (default=30)
-angbl3    (default=78)
-angbl4    (default=120)
-angq1     (default=120)
-angq2     (default=130)
-angq1i    (default=130)
-angq2i    (default=170)
-angscbd   (default=35)
-cbrm      (default=1.75)
-cbsmth    (default=0.5)
-cdfarbl   (default=2)
-cdfbls    (default=0.25)
-cdfbrm    (default=2)
-cdff      (default=1.5)
-cdffbl    (default=1.75)
-cdffp     (default=2)
-cdfm      (default=0)
-cdfn      (default=0.7)
-cdfr      (default=1.3)
-cdsd      (default=3)
-cdsmmax   (default=10)
-cskwmx    (default=0.5)
-csmin     (default=0.5)
-csmin0    (default=0.875)
-csmth     (default=0.5)
-ctol      (default=0.94)
-darbl     (default=0.3)
-dssmth    (default=2)
-relem0    (default=0.1)
-sbmin     (default=0.001)
-vsmthb    (default=0.5)
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Input Files
-----------

 case.bedge       : formatted ascii type BEDGE input grid file

 case.bedge       : optional formatted ascii type BEDGE grid file
 case.fgrid       : optional formatted ascii type FGRID grid file
 case.ugrid       : optional formatted ascii type UGRID grid file
 case.grid        : optional formatted ascii type GRID grid file
 case.fpoin       : optional formatted ascii fixed field point file
 case.fsurf       : optional formatted ascii fixed field surface file
 case.psrc        : optional formatted ascii point source file

Output Files
------------

 case.fgrid             : optional formatted ascii type FGRID grid file
 case.ugrid             : optional formatted ascii type UGRID grid file
 case.grid              : optional formatted ascii type GRID grid file
 case.gqual.out         : text file with distributions of element angles
 case.gqual.data        : data file with distributions of element angles

 case.gqual.out         : optional text file with distributions of element
                          angles, element skewness, and maximum element
                          edge length ratio (with -qm 3 option)
 case.gqual.angle.data  : optional data file with distributions of element
                          angles (with -qm 3 option)
 case.gqual.skew.data   : optional data file with distributions of element
                          skewness (with -qm 3 option)
 case.gqual.lratio.data : optional data file with distributions of maximum
                          element edge length ratio (with -qm 3 option)

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File format for type BEDGE input grid file case.bedge [See also g2r00.f]
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 nbsurf  : number of boundary surfaces
 nbg     : number of boundary groups or objects
 npoin   : number of points

 ibcibs  : boundary condition flag for each boundary surface
 nbspbg  : number of boundary surfaces or segments for each boundary group

 ds      : desired initial boundary-layer normal spacing for each boundary point
 x       : x and y coordinates for each point

 format  : format is free format or * for formatted ascii files

 read (io,format) nbg
 read (io,format) (nbspbg(ibg),ibg=1,nbg)
 read (io,format) (nbppbs(ibsurf),ibsurf=1,nbsurf)
 read (io,format) (ibcibs(ibsurf),ibsurf=1,nbsurf
 read (io,format) ((x(igeomd,ipoin),igeomd=1,2),ipoin=1,npoin)
 read (io,format) (ds(ipoin),ipoin=1,npoin) <-- OPTIONAL (OR SET BY AFLR2)

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File format for input/output type 2D FGRID grid file case.fgrid
[See also doc/ug_io/UG_IO_2D_GRID_FILE_*.*]
[See also g2r01.f and g2w010.f]
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 nbface  : number of boundary faces
 nelem   : number of triangular elements
 npoin   : number of points

 ibcibf  : boundary condition flag for each boundary face
 ipibf   : boundary face connectivity containing two point numbers for each
           boundary face and a boundary surface number in the fourth location
 ipiel   : element connectivity containing three point numbers for each
           triangular element

 ds      : desired initial boundary-layer normal spacing for each boundary point
 x       : x and y coordinates for each point

 format  : format is free format or * for formatted ascii files

 idummy=0
 xdummy=0.0
 read/write (io,format) npoin,nelem,idummy
 read/write (io,format) ((x(igeomd,ipoin),ipoin=1,npoin),igeomd=1,2),
                         (xdummy,ipoin=1,npoin),
                        ((ipiel(ieln,ielem),ieln=1,3),ielem=1,nelem),
                        (idummy,ielem=1,nelem)
 read/write (io,format) nbface
 read/write (io,format) ((ipibf(ibfn,ibface),ibfn=1,2),ibface=1,nbface),
                         (ipibf(4,ibface),ibface=1,nbface)
 read/write (io,format) (ibcibf(ibface),ibface=1,nbface
 read/write (io,format) (ds(ipoin),ipoin=1,npoin) <-- OPTIONAL (OR SET BY AFLR2)

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File format for input/output type 2D UGRID grid file case.fgrid
[See also doc/ug_io/UG_IO_2D_GRID_FILE_*.*]
[See also g2r02.f and g2w020.f]
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 nbface  : number of boundary faces
 nelem   : number of triangular elements
 nquad   : number of quadrilateral elements
 npoin   : number of points

 ipibf   : boundary face connectivity containing two point numbers for each
           boundary face and a boundary surface number in the fourth location
 ipiel   : element connectivity containing three point numbers for each
           triangular element
 ipiq    : element connectivity containing four point numbers for each
           quadrilateral element

 x       : x and y coordinates for each point

 format  : format is free format or * for formatted ascii files

 idummy=0
 xdummy=0.0
 read/write (io,format) npoin,nelem,nquad,idummy,idummy,idummy,idummy
 read/write (io,format) (x(1,ipoin),x(2,ipoin),xdummy,ipoin=1,npoin),
                        ((ipiel(ieln,ielem),ieln=1,3),ielem=1,nelem),
                        ((ipiq(ieln,iquad),ieln=1,4),iquad=1,nquad),
                        (idummy,ielem=1,nelem+ntria)
 read/write (io,format) nbface
 read/write (io,format) ((ipibf(ibfn,ibface),ibfn=1,2),ibface=1,nbface),
                         (ipibf(4,ibface),ibface=1,nbface)

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File format for input/output type 2D GRID grid file case.grid
[See also doc/ug_io/UG_IO_2D_GRID_FILE_*.*]
[See also g2r03.f and g2w03.f]
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 nbface  : number of boundary faces
 nelem   : number of triangular elements
 npoin   : number of points

 ipibf   : boundary face connectivity containing two point numbers for each
           boundary face and a boundary surface number in the fourth location
 ipiel   : element connectivity containing three point numbers for each
           triangular element

 x       : x and y coordinates for each point

 format  : format is free format or * for formatted ascii files

 read/write (io,format) nelem,npoin,nbface
 read/write (io,format) ((ipiel(ieln,ielem),ielem=1,nelem),ieln=1,3)
 read/write (io,format) ((x(igeomd,ipoin),ipoin=1,npoin),igeomd=1,2)

 read/write (io,format) ((ipibf(ibfn,ibface),ibface=1,nbface),ibfn=1,2),
                         (ipibf(4,ibface),ibface=1,nbface)

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File format for input/output type 3D FGRID grid file case.fgrid
[See doc/ug_io/UG_IO_3D_GRID_FILE_*.*]
[See also g2w011.f and g2w012.f]
--------------------------------------------------------------------------------

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File format for input/output type 3D UGRID grid file case.ugrid
[See doc/ug_io/UG_IO_3D_GRID_FILE_*.*]
[See also g2w021.f and g2w022.f]
--------------------------------------------------------------------------------

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File format for type FPOIN input point source file case.fpoin
[See also g2rfp.f and g2xread.f]
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 nfpoin  : number of fixed field points
 nfpoind : maximum number of fixed field points

 dff     : desired point spacing for each fixed field point
 xf      : x and y coordinates for each fixed field point

   do ifpoin=1,nfpoind
      read(io,*,end=1)x1,x2,df0
      dff(ifpoin)=df0
      xf(1,ifpoin)=x1
      xf(2,ifpoin)=x2
   enddo
1  continue
   nfpoin=ifpoin-1

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File format for type FSURF input point source file case.fsurf
[See also g2rfs.f]
--------------------------------------------------------------------------------

 nbsurf  : number of boundary surfaces
 nfspoin : number of fixed field points
 nfsg    : number of fixed field surfaces
 nfsgd   : maximum number of fixed field surfaces

 ibcibs  : boundary condition flag for each boundary surface
           additional boundary surfaces are created for each fixed field surface
           two are created for each side of the fixed field surface and an
           additional two are created at each end point for the connecting
           surface if the end point connects to an existing point
 ipifsg  : fixed field surface information
           in the first location is the index of the existing boundary point
           which connects with the first point of the fixed field surface
           if the index is zero then the first end point does not connect to any
           other point
           in the second location is the index of the existing boundary point
           which connects with the last point of the fixed field surface
           if the index is zero then the last end point does not connect to any
           other point
           if the index is negative one then the last end point connects to the
           first end point (note: this overides the index in the first location)
           in the third location is the grid boundary condition for the fixed
           field surface
 nppfsg  : number of points in each fixed field surface

 dsfs    : desired initial boundary-layer normal spacing for each fixed field
           surface point (REQUIRED BUT VALUE IS IGNORED IF RESET BY AFLR2)
 xfs     : x and y coordinates for each fixed field surface point

   ibsurf=nbsurf
   ifspoin2=0
   do ifsg=1,nfsgd
      ibsurf=ibsurf+1
      ipifsg(3,ifsg)=ibsurf
      read(iofsurf,*,end=1)nppfsg(ifsg),ipifsg(1,ifsg),ipifsg(2,ifsg),ibc
      ifspoin1=ifspoin2+1
      ifspoin2=ifspoin2+nppfsg(ifsg)
      jbsurf=ibsurf+1
      if(ipifsg(1,ifsg).gt.0)jbsurf=jbsurf+2
      if(ipifsg(2,ifsg).gt.0)jbsurf=jbsurf+2
      do kbsurf=ibsurf,jbsurf
         ibcibs(kbsurf)=ibc
      enddo
      ibsurf=jbsurf
      do ifspoin=ifspoin1,ifspoin2
         read(iofsurf,*)xfs(1,ifspoin),xfs(2,ifspoin),dsfs(ifspoin)
      enddo
   enddo
1  continue
   nfsg=ifsg-1

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File format for type PSRC input point source file case.psrc
[See also g2rfp.f and g2xread.f]
--------------------------------------------------------------------------------

 npsrc   : number of point sources
 npsrcd  : maximum number of point sources

 dfps    : desired point spacing for each point source
 xps     : x and y coordinates for each point source

   do ipsrc=1,npsrcd
      read(io,*,end=1)x1,x2,df0
      dfps(ipsrc)=df0
      xps(1,ipsrc)=x1
      xps(2,ipsrc)=x2
   enddo
1  continue
   npsrc=ipsrc-1

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File Last Updated Sun Mar 21 13:01:09 CDT 2021