.TH "mkgeo_contraction" 1rheolef "Version 7.2" "rheolef" \" -*- nroff -*-
.ad l
.nh
.SH NAME
mkgeo_contraction \- mesh of an abrupt contraction (rheolef-7\&.2)
.PP
    
.SH "SYNOPSIS"
.PP
.nf
mkgeo_contraction [options] [nx [ny]]
.fi
.PP
 
.SH "EXAMPLE"
The following command build a triangle-based 2d unstructured mesh of the [-10,0]x[0,4] u [0,10]x[0,1] mesh 
.PP
.nf
    mkgeo_contraction
    geo contraction\&.geo

.fi
.PP
 
.SH "DESCRIPTION"
This command is convenient for building a mesh for the abrupt contraction, as it is a very classical benchmark in complex fluid flow problems\&. It calls \fCbamg\fP unstructured mesh generator with anisotropy feature\&. The mesh files goes on name\&.geo where \fIname\fP is the basename for the output (see option \fC-name\fP below)\&. The three auxiliary files required for automatic mesh generation with Rheolef combined with \fCbamg\fP are also provided: 
.PP
.nf
        name\&.bamg
        name\&.bamgcad
        name\&.dmn

.fi
.PP
 
.SH "THE GEOMETRY"
The geometry is [-Lu,0]x[0,d] u [0,Ld]x[0,1]\&. By default c=4 is the contraction ratio and Lu=Ld=10 are the upstream and downstream pipe lengths\&.
.PP
\fC-c\fP \fIfloat\fP 
.br
\fC-Lu\fP \fIfloat\fP 
.br
\fC-Ld\fP \fIfloat\fP 
.PP
.RS 4
 These options control the geometry parameters\&. 
.RE
.PP
\fC-cartesian\fP 
.br
\fC-zr\fP 
.br
\fC-rz\fP 
.PP
.RS 4
 These options control the geometry coordinate system\&. Default is Cartesian\&. 
.RE
.PP
.SH "THE DISCRETIZATION"
The optional \fInx\fP and \fIny\fP arguments are integers that specifies the subdivision in each direction\&. By default nx=1 and ny=nx\&. Changing the density applies the factor 1/nx to all the mesh edges lengths\&.
.PP
\fC-hmin\fP \fIfloat\fP 
.PP
.RS 4
 Controls the edge length at the re-entrant corner of the contraction\&. Default is \fChmin\fP=0\&.1\&. Changing the density by the previous options applies the factor 1/n to \fChmin\fP also\&. 
.RE
.PP
.SH "BOUNDARY DOMAINS"
The boundary sides are represented by domains: \fCaxis\fP, \fCwall\fP, \fCupstream\fP and \fCdownstream\fP\&.
.SH "OTHERS OPTIONS"
\fC-name\fP \fIstring\fP 
.PP
.RS 4
 Set the basename for the output files\&. By default, the basename is \fCcontraction\fP\&. 
.RE
.PP
\fC-[no]split\fP 
.PP
.RS 4
 Split each triangle in three subtriangles by inserting the barycenter as an additional node\&. This is useful for using the Scott and Vogelius incompressible mixed finite element P2-P1d for velocity-pressure approximation\&. Default is no split\&. 
.RE
.PP
\fC-[no]clean\fP 
.PP
.RS 4
 Clear temporary files (this is the default)\&.
.PP
.RE
.PP
\fC-[no]verbose\fP 
.PP
.RS 4
 In verbose mode, print to stderr all commands and logs\&. 
.RE
.PP
.SH "IMPLEMENTATION"
This documentation has been generated from file main/sbin/mkgeo_contraction\&.sh 
.SH AUTHOR
Pierre  Saramito  <Pierre.Saramito@imag.fr>
.SH COPYRIGHT
Copyright   (C)  2000-2018  Pierre  Saramito  <Pierre.Saramito@imag.fr>
GPLv3+: GNU GPL version 3 or later  <http://gnu.org/licenses/gpl.html>.
This  is  free  software:  you  are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.