2. Digital aspects

2.1 Structured or unstructured mesh

Historically, the first CFD codes worked with structured meshes, i.e. hexahedral volumes arranged in a 3D matrix according to a Cartesian system. Then came the possibility of processing the combination of several structured zones, known as "multiblock", which made it possible to handle more complicated geometries, but the meshing stage remained tedious. Solutions have also been proposed for working with coordinate systems other than Cartesian.

Figure 1 shows an example...