Page 219 - Basic Structured Grid Generation

208 Basic Structured Grid Generation

A B
6 5 4

7
3
2

8
C 1 D
Fig. 8.23 Domain for AFT with background grid.

5
6 4

7 3
K id 2

8
1
Fig. 8.24 First front with ideal point.

Nodes 1 to 8 are chosen, and the first front is shown in Fig. 8.24. One of the
two shortest faces (1-2) is chosen and an ideal point is constructed as shown in the

same figure. The circle of radius δ is also indicated. This contains no nodes, and the
equilateral triangle created is valid. Hence the ideal point is acceptable, and can be
taken as a new node. The front is now updated. As shown in Fig. 8.25 we have:

• active nodes: 1, 9, 2, 3, 4, 5, 6, 7, 8
• active sides: 1-9, 9-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-1
• passive nodes: none
• passive faces; 1-2
• npoint (total number of points): 9
• nelem (total number of elements created): 1
• nptr (number of points remaining, i.e. active nodes): 9

Next the face 2-3 is chosen. This leads to a similar construction to that in the previous
step, as shown in Fig. 8.26, where again the ideal point is acceptable and taken as the
new node. The updated front is shown in Fig. 8.27, with