Download ME 566 Computational Fluid Dynamics for Fluids Engineering

CHAPTER 3. GEOMETRY AND MESH SPECIFICATION
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Figure 3.4: Meshes showing the influence of edge sizing specification on mesh blocking. The mesh on the left has edge sizing set on the two left vertical edges. The mesh
on the right has edge sizing set on right and left vertical edges.
Type:
Element Size: sets the average of the elements lengths, ∆, along the
edge; or
Number of Divisions: sets the number, N , of elements along the edge;
Note that L = N ∆ where L is the edge length.
Edge Behaviour: sets whether the mesh spacing and placement are rigidly
enforced, Edge Behaviour È Hard , or can be modified by the automatic
meshing routines, Edge Behaviour È Soft ;
Bias: sets the placement of vertices along an edge to one of the following patterns: None or uniform spacing, Decreasing spacing, Increasing spacing, Increasing-Decreasing spacing, and Decreasing-Increasing spacing.
For each pattern, the mesh spacing increases or decreases by a fixed expansion ratio, r , between adjacent elements. Table 3.1 gives relationships between edge length, number of elements, expansion ratio, bias
factor, and smallest and largest element lengths.
The bias direction is automatically determined in the blocking algorithm.
Bias Factor: Is the ratio of largest element length to the smallest element
length along an edge.
CFX-Mesh: Free Tet Meshing with Inflation
The following comments and guidelines are for generating tetrahedral meshes with
surface inflation for two-dimensional flow simulation in relatively simple geometries.