NAME

       mkgeo_contraction - mesh of an abrupt contraction (rheolef-7.1)

SYNOPSIS

       mkgeo_contraction [options] [nx [ny]]

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

           mkgeo_contraction
           geo contraction.geo

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 bamg unstructured mesh generator with anisotropy
       feature. The mesh files goes on name.geo where name is the basename for the output (see option -name
       below). The three auxiliary files required for automatic mesh generation with Rheolef combined with bamg
       are also provided:

               name.bamg
               name.bamgcad
               name.dmn

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.

       -c float
       -Lu float
       -Ld float

           These options control the geometry parameters.

       -cartesian
       -zr
       -rz

           These options control the geometry coordinate system. Default is Cartesian.

THE DISCRETIZATION

       The optional nx and ny 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.

       -hmin float

           Controls the edge length at the re-entrant corner of the contraction. Default is hmin=0.1. Changing
           the density by the previous options applies the factor 1/n to hmin also.

BOUNDARY DOMAINS

       The boundary sides are represented by domains: axis, wall, upstream and downstream.

OTHERS OPTIONS

       -name string

           Set the basename for the output files. By default, the basename is contraction.

       -[no]split

           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.

       -[no]clean

           Clear temporary files (this is the default).

       -[no]verbose

           In verbose mode, print to stderr all commands and logs.

IMPLEMENTATION

       This documentation has been generated from file main/sbin/mkgeo_contraction.sh

AUTHOR

       Pierre  Saramito  <Pierre.Saramito@imag.fr>

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.