I suppose the elements follow the orientation of the loop or surface.<br><br>Just use:<br>ex:<br>Plane Surface(10) = {-8} ;<br><br>instead of:<br>Plane Surface(10) = {8} ;<br>
<br>to invert the ones you want.<br><br>Regards,<br><br>Billy.<br><br><div class="gmail_quote">On Mon, Mar 29, 2010 at 3:53 PM, Umut Tabak <span dir="ltr"><<a href="mailto:u.tabak@tudelft.nl">u.tabak@tudelft.nl</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Dear all,<br>
<br>
I am trying to model a 2 domain problem for a simple 2d academic case study. I have a structural region on the upper side of the model, and a fluid domain below. However there is a problem with the element node orders in domains of fluid and structure. You can see the what I mean in the attached png. 1 is the structural domain and 2 is the fluid domain. But there is a problem which I could not solve, if I create the two surfaces separately and mesh them, I am getting the node orders of region 1 wrong. What I mean is: for instance for an element, say 326, in domain 2, I get<br>
<br>
<br>
393____412<br>
| |<br>
| |<br>
|392___411<br>
<br>
and the ordering in the msh file is<br>
<br>
326 3 3 1 10 0 392 411 412 393<br>
<br>
But for an element in domain 1, say 785,<br>
<br>
813____822<br>
| |<br>
| |<br>
812____821<br>
<br>
but the ordering in the msh file is given as<br>
<br>
785 3 3 2 11 0 812 813 822 821<br>
<br>
I did not understand the cause of this problem I am facing.<br>
<br>
Most probably, there is sth I am missing in the definitions of the domains and line loops but could not find myself. geo file is also attached.<br>
<br>
Any help is appreciated, thx in advance and regards,<br><font color="#888888">
<br>
Umut<br>
</font><br>/*********************************************************************<br>
*<br>
* Gmsh tutorial 1<br>
*<br>
* Variables, elementary entities (points, lines, surfaces), physical<br>
* entities (points, lines, surfaces)<br>
*<br>
*********************************************************************/<br>
<br>
// The simplest construction in Gmsh's scripting language is the<br>
// `affectation'. The following command defines a new variable `lc':<br>
<br>
lc = 0.05;<br>
<br>
// This variable can then be used in the definition of Gmsh's simplest<br>
// `elementary entity', a `Point'. A Point is defined by a list of<br>
// four numbers: three coordinates (X, Y and Z), and a characteristic<br>
// length (lc) that sets the target element size at the point:<br>
Point(1) = {0, 0, 0, lc};<br>
// The distribution of the mesh element sizes is then obtained by<br>
// interpolation of these characteristic lengths throughout the<br>
// geometry. Another method to specify characteristic lengths is to<br>
// use a background mesh (see `t7.geo' and `bgmesh.pos').<br>
// We can then define some additional points as well as our first<br>
// curve. Curves are Gmsh's second type of elementery entities, and,<br>
// amongst curves, straight lines are the simplest. A straight line is<br>
// defined by a list of point numbers. In the commands below, for<br>
// example, the line 1 starts at point 1 and ends at point 2:<br>
Point(2) = {1.0, 0.0, 0.0, lc} ;<br>
Point(3) = {1.0, 0.45, 0.0, lc} ;<br>
Point(4) = {0.0, 0.45, 0.0, lc} ;<br>
// add interface region<br>
Point(5) = {0.0, 0.5, 0.0, lc} ;<br>
Point(6) = {1.0, 0.5, 0.0, lc} ;<br>
// the acoustic only domain<br>
Line(1) = {1,2} ;<br>
Line(2) = {2,3} ;<br>
Line(3) = {3,4} ;<br>
Line(4) = {4,1} ;<br>
// interface domain is created<br>
Line(5) = {4,5} ;<br>
Line(6) = {5,6} ;<br>
Line(7) = {6,3} ;<br>
// The third elementary entity is the surface. In order to define a<br>
// simple rectangular surface from the four lines defined above, a<br>
// line loop has first to be defined. A line loop is a list of<br>
// connected lines, a sign being associated with each line (depending<br>
// on the orientation of the line):<br>
Transfinite Line{ 1, 3, 6} = 31 ;<br>
Transfinite Line{ 2, 4 } = 21 ;<br>
Transfinite Line{ 5, 7 } = 11 ;<br>
//<br>
Line Loop(8) = { 1, 2, 3, 4 } ;<br>
Line Loop(9) = { 3, 7, 6, 5 } ;<br>
// We can then define the surface as a list of line loops (only one<br>
// here, since there are no holes--see `t4.geo'):<br>
Plane Surface(10) = {8} ;<br>
Plane Surface(11) = {9} ;<br>
//<br>
Transfinite Surface{10} = { 1, 2, 3, 4 };<br>
Transfinite Surface{11} = { 4, 3, 6 ,5 };<br>
// Recombine the triangles into quads<br>
Recombine Surface{10};<br>
Recombine Surface{11};<br>
// Consequently, two punctual elements will be saved in the output<br>
// mesh file, both with the region number 1. The mechanism is<br>
// identical for line or surface elements:<br>
// bc line applied<br>
Physical Line(1) = {5,7} ;<br>
// interface line<br>
Physical Line(2) = {3};<br>
//<br>
Physical Surface(1) = {10} ;<br>
Physical Surface(2) = {11} ;<br>
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<br></blockquote></div><br>