The finite element mesh, boundary conditions and the fluid properties are stored in the gridfile, *.grf. Data in the gridfile are grouped into seven distinct blocks. Entered in a free format, the data in each block is stored within the key words BEGIN and END. These data blocks are:
NODES | 
Coordinates of the nodes.  | 
ELEMENTS | 
Node connectivity to define the cells and material properties.  | 
BOUNDARY | 
Define boundary conditions  | 
BCASSIGN | 
Assign boundary conditions to element/cell faces.  | 
MATERIAL | 
Define material properties  | 
MATASSIGN | 
Assign element material identifiers to MATERIAL  | 
FUNCTIONS | 
Define data in the form of a function (table/expression)  | 
PROBLEMDATA | 
Specify solution extract points  |