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<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 3.2 Final//FR"><!-- Converted with LaTeX2HTML 95.1 (Fri Jan 20 1995) --><!-- by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds --><!-- Modified Simulog 03/97 --><HTML><HEAD><TITLE>3.3.1 Quick description of the method</TITLE><LINK REL=STYLESHEET TYPE="text/css" HREF="./Modulef.css" TITLE="Modulef CSS"><meta name="description" value="3.3.1 Quick description of the method"><meta name="keywords" value="Guide3"><meta name="resource-type" value="document"><meta name="distribution" value="global"></HEAD><BODY BGCOLOR="#FFFFFF"><P> <IMG SRC="../icons/smallmod.gif" WIDTH=211 HEIGHT=50 ALIGN=BOTTOM ALT="Modulef"><A NAME=tex2html1507 HREF="node52.html"><IMG BORDER=0 ALIGN=BOTTOM SRC="../icons/previous_motif.gif" ALT="previous"></A><A NAME=tex2html1513 HREF="node52.html"><IMG BORDER=0 ALIGN=BOTTOM SRC="../icons/up_motif.gif" ALT="up"></A><A NAME=tex2html1515 HREF="node54.html"><IMG BORDER=0 ALIGN=BOTTOM SRC="../icons/next_motif.gif" ALT="next"></A><A NAME=tex2html1517 HREF="node2.html"><IMG BORDER=0 ALIGN=BOTTOM SRC="../icons/contents_motif.gif" ALT="contents"></A><A NAME=tex2html1518 HREF="node28.html"><IMG BORDER=0 ALIGN=BOTTOM SRC="../icons/index_motif.gif" ALT="index"></A><A HREF="../Guide3-18/node53.html"><IMG BORDER=0 SRC="../icons/zoom18.gif" ALIGN=BOTTOM ALT="[BIG]"></A><A HREF="../Guide3-14/node53.html"><IMG BORDER=0 SRC="../icons/zoom14.gif" ALIGN=BOTTOM ALT="[Normal]"></A><A HREF="../Guide3-10/node53.html"><IMG BORDER=0 SRC="../icons/zoom10.gif" ALIGN=BOTTOM ALT="[small]"></A><BR><B> Next: </B> <A NAME=tex2html1516 HREF="node54.html">3.3.2 Simplified version</A><B>Up: </B> <A NAME=tex2html1514 HREF="node52.html">3.3 Extrusion method (cylindrical topology)</A><B> Prev: </B> <A NAME=tex2html1508 HREF="node52.html">3.3 Extrusion method (cylindrical topology)</A><B><A HREF="node28.html" >Index</A></B><B><A HREF="node2.html" >Contents</A></B><HR SIZE=3 WIDTH="75%"><H2><A NAME=SECTION00631000000000000000>3.3.1 Quick description of the method</A></H2><P>This method enables us to construct a mesh of all domains with a cylindrical topology from a 2D reference meshby stacking layers of 3D elements. The nature of the 3D elements is deduced from that of the 2D elements ofthe reference mesh.<P>In fact, all domains which are possible to define in this fashion are said to be topologically cylindrical.<P>The data corresponding to this mesh generator is therefore the 2D mesh of a reference section and the definition of the sections along the generating axis.<P><P><A NAME=4887> </A><IMG BORDER=0 ALIGN=BOTTOM ALT="" SRC="img136.gif"><BR><STRONG>Figure 3.8:</STRONG> <i> Correspondence 2D - 3D</i><A NAME=4883iCorrespondence2D3Di4883> </A><BR><P><P>This method is known as the translation-stacking method<A NAME=4625> </A> or extrusion method.<P>Segments in the space are associated to the points of a 2D mesh, quadrangular layers in the space are associatedto the segments in the 2D mesh, pentahedra are associated to the triangles, and hexahedra are associated to the quadrilaterals. The connectivity is deduced from that of the two-dimensional basis mesh and from the section index.<P>In order to be able to treat domains containing the axis of the associated cylinder, it is necessary to considerthe cases of possible degeneracy (see example), such as a quadrilateral giving rise to the creation of pentahedra and not hexahedra.<P>As input data, this mesh generator requires a two-dimensional mesh of a section representing thedomain and the definition of a transport function for this section used to define the set of layersfor the stacking to be realized.<P>The efficiency of this method results form several possibilities offered to define the coordinates of thevertices of the sections, either directly from the 2D basis mesh, or section by section from the definitionof a starting section. A 3D vertex is known by the 2D vertex from which it is deduced as well as its sectional index, k. Consequently, it suffices to input, according to the case under consideration, the following data:<P><UL><LI> Mesh with a constant step in the direction of the cylindrical axis: the step corresponding to the spacing ofthe points in this direction;<LI> Mesh with a variable step in the direction of this axis: the corresponding steps in the form of an array;<LI> Arbitrary transport of the basis section: in the form of functions, the mapping gives the three coordinates of the points from the two coordinates of the corresponding basis point and the sectional index;<LI> Arbitrary transport from a section constructed previously: in the form of functions, the mapping gives the three coordinates of the points in the section to be created, in terms of the coordinates of the associated point of thepreceding section. </UL><P>The face, edge and point references of the mesh created are defined by the user, as well as the sub-domain numbers of the elements created; these values are deduced, according to a given correspondence (see below), fromthe values present in the initial mesh.<P><P><P><HR SIZE=3 WIDTH="75%"><IMG SRC="../icons/smallmod.gif" WIDTH=211 HEIGHT=50 ALIGN=BOTTOM ALT="Modulef"><A NAME=tex2html1507 HREF="node52.html"><IMG BORDER=0 ALIGN=BOTTOM SRC="../icons/previous_motif.gif" ALT="previous"></A><A NAME=tex2html1513 HREF="node52.html"><IMG BORDER=0 ALIGN=BOTTOM SRC="../icons/up_motif.gif" ALT="up"></A><A NAME=tex2html1515 HREF="node54.html"><IMG BORDER=0 ALIGN=BOTTOM SRC="../icons/next_motif.gif" ALT="next"></A><A NAME=tex2html1517 HREF="node2.html"><IMG BORDER=0 ALIGN=BOTTOM SRC="../icons/contents_motif.gif" ALT="contents"></A><A NAME=tex2html1518 HREF="node28.html"><IMG BORDER=0 ALIGN=BOTTOM SRC="../icons/index_motif.gif" ALT="index"></A><A HREF="../Guide3-18/node53.html"><IMG BORDER=0 SRC="../icons/zoom18.gif" ALIGN=BOTTOM ALT="[BIG]"></A><A HREF="../Guide3-14/node53.html"><IMG BORDER=0 SRC="../icons/zoom14.gif" ALIGN=BOTTOM ALT="[Normal]"></A><A HREF="../Guide3-10/node53.html"><IMG BORDER=0 SRC="../icons/zoom10.gif" ALIGN=BOTTOM ALT="[small]"></A><BR><B> Next: </B> <A NAME=tex2html1516 HREF="node54.html">3.3.2 Simplified version</A><B>Up: </B> <A NAME=tex2html1514 HREF="node52.html">3.3 Extrusion method (cylindrical topology)</A><B> Prev: </B> <A NAME=tex2html1508 HREF="node52.html">3.3 Extrusion method (cylindrical topology)</A><B><A HREF="node28.html" >Index</A></B><B><A HREF="node2.html" >Contents</A></B><BR> <HR><P><ADDRESS></ADDRESS></BODY></HTML>⌨️ 快捷键说明
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