ICEM Tetra automatically fills an arbitrary space and voids enclosed by an assembly of CAD patches with tetrahedron elements. There are several options for improving and modifying tetrahedral meshes. We are going to explain here the two options : the Smoother and the Coarsener.
We have explained how to mesh the geometry in the "Creating a semicylinder" part. But like this, the mesh is not optimised because it doesn't use tools of optimisation as the Smoother and the Coarsener.
So without Smoother and without Coarsener, the mesh
is like above (following different views) :
Mesh without Smoother and without Coarsener (green: wall - blue: symetry - yellow: outlet and inlet)
We can notice that the mesh is formed by a structured assembly (in hexadral) of tetrahedron elements. It is not a optimal mesh which should be formed by more unstructured assembly of elements.
The tetrahedral smoother first calculates the relative
aspect ratio (obtained by calculating the ratio between the volume of the
element and that of the largest tetrahedron that could fit inside the sphere
that circumscribes the actual one) of each cell. The user specifies the
quality limit and number of iterations (Aspect Ratio and Iterations).
The smoother then modifies elements below the quality criteria. Nodes are moved and merged, edges are swapped, and in some cases elements are deleted. The operation is automatically repeated on the improved grid, up to the specified number of iterations.
Mesh with the Smoother and without Coarsener
The coarsener reduces the number of triangles in
a mesh by merging multiple triangles into one.
There is one parameter to regle for the Coarsener: Aspect Ratio to increase more or less the propriety of the Coarsener.
Mesh with the Smoother and the Coarsener