If the maximum tetrahedral size defined on a surface is larger than needed to resolve the feature, you can employĬurvature/Proximity Based Refinement to automatically subdivide the mesh to capture the feature. The following sections describe important features of tetra meshing. Figure 30: Final Mesh after smoothingĬontains proprietary and confidential information of ANSYS, Inc. Tetra then "cuts away" all of the mesh, which cannot be reached by a user-defined material point without intersection of a surface.įigure 28: Mesh after it captures surfaces and separation of useful volume 第23页įinally, the mesh is smoothed by moving nodes, merging nodes, swapping edges and in some cases, deleting bad elements. The mesh does not yet match the given geometry, so the mesher next rounds the nodes of the mesh to the prescribed points, prescribed curves or model surfaces.
#Ansys icem cfd meshing full#
Once the "root" tetrahedron, which encloses the entire geometry, has been initialized, Tetra subdivides the root tetrahedron until all element size requirements are met.Īt this point, the Tetra mesher balances the mesh so that elements sharing an edge or face do not differ in size by more than a factor of 2.įigure 25: Full Tetra Enclosing the Geometryįigure 26: Full Tetra Enclosing the Geometry in Wire Frame Mode 第22页Īfter this is done, Tetra makes the mesh conformal - that is, it guarantees that each pair of adjacent elements will share an entire face. The Octree mesh method is based on the following spatial subdivision algorithm: This algorithm ensures refinement of the mesh where necessary, but maintains larger elements where possible, allowing for faster computation. If there are many problem areas, it may be better to repair the geometry or adjust the meshing 第21页 Further holes would be flagged and repaired in the same manner.
To repair the hole, select the single edges bounding it - and the mesher will loft a surface mesh to close the hole. The elements surrounding the hole will also be displayed. If holes are found, the Message window will display a message like "Material point ORFN can reach material point LIVE." You will be prompted with a dialog box saying, "Your geometry has a hole, do you want to repair it?" A jagged line will display the leakage path from the ORFN part to the LIVE part. A hole is usually considered a space that is greater than 2 or 3 elements in thickness.ĭuring the process of finding the bounding surfaces to close the volume mesh, the mesher will determine if there are holes in the model. Since the gap may be confused as a hole, you should either define a thin cut, in order to establish that the gap is not a hole or make the mesh size small enough so that it won't close the gap when the meshing is performed. The Tetra mesher automatically attempts to close all holes in a model. These non-manifold vertices would be created during the meshing process. If the tetra sizes are larger or approximately the same size as the gap between the surfaces or curves, the surface mesh could have a tendency to jump the gap, thus creating non-manifold vertices. If the surfaces meet, the curve at the intersection of the surfaces will need to be in a different part. To define a thin cut, the two surfaces have to be in different Parts. This option is in the Mesh > Global Mesh Setup > Volume Meshing Parameters section. (This would also apply if the region outside the geometry has small angles.) If the local tetra sizes are not small enough so that at least 1 or 2 elements would fit through the thickness, you should define thin cuts. Meshing Inside Small Angles or in Small Gaps Between ObjectsĮxamine the regions between two surfaces or curves that are very close together or that meet at a small angle. Note that if the Scale Factor is assigned a value of 0, the Tetra mesher will not run. To modify the mesh size for all entities, adjust the Scale Factor, which is found under Mesh > Global Mesh Setup. In this case, modify the mesh parameters so that the icons are visible in a normal display.
If a curve or surface does not have an icon plotted on it, the icon may be too large or too small to see. Using the mouse, you may rotate the model and visually confirm that the tetra sizes are appropriate. Tetra icons will appear, representing the element size of the mesh to be created on these entities.
For a visual representation of the mesh size, select Geometry > Surfaces > Tetra Sizes from the Display Tree. To produce the optimal mesh, it is essential that all surfaces and curves have the proper tetra sizes assigned to them. and its subsidiaries and affiliates.ĪNSYS ICEM CFD 14.5 - © SAS IP, Inc. Contains proprietary and confidential information of ANSYS, Inc.
0 kommentar(er)
