NAME¶

mkgeo_grid -- build a strutured mesh of a parallelotope, in 1d, 2d or 3d

SYNOPSIS¶

        mkgeo_grid  options [nx [ny [nz]]]
 

EXAMPLE¶

The following command build a triangular based 2d 10x10 grid of the unit square:

        mkgeo_grid -t 10 > square-10.geo
        geo square-10.geo
 

or in one comand line:

        mkgeo_grid -t 10 | geo -
 

DESCRIPTION¶

This command is usefull when testing programs on simple geometries. It avoid the preparation of an input file for a mesh generator. The optional nx, ny and nz arguments are integer that specifies the subdivision in each direction. By default nx=10, ny=nx and nz=ny. The mesh files goes on standard output. The command supports all the possible element types: edges, triangles, rectangles, tetraedra, prisms and hexahedra.

ELEMENT TYPE OPTIONS¶

-e

1d mesh using edges.

-t

2d mesh using triangles.

-q

2d mesh using quadrangles (rectangles).

-T

3d mesh using tetraedra.

-P

3d mesh using prisms.

-H

3d mesh using hexahedra.

THE GEOMETRY¶

The geometry can be any [a,b] segment, [a,b]x[c,d] rectangle or [a,b]x[c,d]x[f,g] parallelotope. By default a=c=f=0 and b=d=g=1, thus, the unit boxes are considered. For instance, the following command meshes the [-2,2]x[-1.5, 1.5] rectangle:

        mkgeo_grid -t 10 -a -2 -b 2 -c -1.5 -d 1.5 | geo -
 

-a float

-b float

-c float

-d float

-f float

-g float

BOUNDARY DOMAINS¶

-sides

-nosides

The boundary sides are representd by domains: left, right, top, bottom,front and back.

-boundary

-noboundary

This option defines a domain named boundary that groups all sides. By default, both sides and the whole boundary are defined as domains:

 

        mkgeo_grid -t 10 > square.geo
       geo square.geo
        mkgeo_grid -t 10 -nosides > square.geo
       geo square.geo
        mkgeo_grid -t 10 -noboundary > square.geo
       geo square.geo
        mkgeo_grid -t 10 -noboundary -nosides > square.geo
       geo square.geo
 
    

REGIONS¶

-region

-noregion

The whole domain is splitted into two subdomains: east and west, This option is used for testing computations with subdomains (e.g. transmission problem; see the user manual).

 

        mkgeo_grid -t 10 -region | geo -
 
    

CORNERS¶

-corner

-nocorner

The corners (four in 2D and eight in 3D) are defined as OD-domains. This could be usefull for some special boundary conditions.

 

        mkgeo_grid -t 10 -corner | geo -
        mkgeo_grid -T  5 -corner | geo -
 
    

COORDINATE SYSTEM OPTION¶

Most of rheolef codes are coordinate-system independant. The coordinate system is specified in the geometry file ` .geo'.

-zr

-rz

the 2d mesh is axisymmetric: zr (resp. rz) stands when the symmetry is related to the first (resp. second) coordinate.

FILE FORMAT OPTION¶