What grid generator is Gerris using?
Gerris uses an “embedded boundary” technique. Grid generation reduces to the computation of the “shape” (surface and volume fractions) of Cartesian (cubic) cells cut by the solid boundaries. These “boolean operations” between solids are performed automatically using GTS (the GNU Triangulated Surface Library). The cells cut by the boundaries can then be refined automatically using the quad/octree structure of the discretisation. Mesh generation is entirely automatic and works for any input geometry (provided it is topologically consistent, i.e. an orientable non-self-intersecting manifold).
