Generation of Computational Mesh for Haemodynamics Analysis - Computational Hemodynamics: Theory, Modelling and Applications - page 163

2D geometry space Initial subdivision Subdivision of lower right

quadrant

A further three recursive subdivisions within one region of the lower right quadrant
until a criterion of a homogeneous space is met.

Fig. 6.11 A quadtree subdivision concentrating only on the bottom right corner region. A criterion
of region filling by the interior of the 90° bend is used. Any region that does not contain any inte-
rior region is neglected. The interior region is shaded to highlight the selected region

Octrees are based on the same principle of divide-and-conquer as in quadtrees
but instead applied to 3D geometries (Fig. 6.12 ). The geometry is subdivided in
the three perpendicular planes. For each subdivision a criterion is used to deter-
mine whether further subdivisions are needed. Overall, the quadtree/octree method
is relatively simple, inexpensive and produces good quality mesh in interior regions
of the domain. One drawback of the method is that it has a tendency to generate

Fig. 6.12 Octree of a simple rectangular geometry