VDF

The Finite Volume Difference (VDF) discretization (class VDF_discretisation and alias VDF) is the simplest and most efficient discretization of the TRUST platform. This discretization is compatible with conform mesh with hexahedral type of elements. Attention: do not confuse between a hexahedral mesh and a cartesian mesh. The VDF mesh is not structured and does not follow the IJK indexing!

As stated by its name, the VDF is a conservative finite volume scheme of Marker-and-Cell (MAC) type, [Harlow et al., 1965]. The discretization of each term of the equation is performed by integrating over a control volume. The diffusion gradient terms are approximated by a linear difference equation. All scalars are stored at the center of each control volume except the velocity field which is defined on a staggered mesh.

This discretization supports 2D axi-symmetrical configurations and is compatible with Pb_Multiphase.

Figure 8 Scheme of a VDF grid: scalars are stored at the center of the elements and normal component of the vorticities at the faces of the element