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VOLFR Command

VOlfr [ [*]FILENAME ] N L [ Xmin Xmax Ymin Ymax Zmin Zmax ] [ 0 ]

Compute material VOLUME FRACTIONS on the rectangular mesh defined with the MESH command.

The volume fraction calculation does not work well with body geometry; the use of surface geometry is strongly encouraged. If Sabrina detects an error when calculating volumes in a mesh cell, the listing for that cell is preceeded with an E.

If present, the fractions are written to file FILENAME. If no name is given, the fractions are written to file volfr. If the file exists, Sabrina will prompt whether or not to overwrite the file unless the name is volfe, in which case it will be overwitten without prompting. If not in quotes, the name, including the asterisk, is limited to 16 characters. If quoted, the limit is 64 characters.

if * is present, the volume fractions are not output to the shell window. The asterisk can be present even if the file name is omitted.

Xmin ... Zmax
If the spatial limits are given, the calculation is restricted to that cube.

If 0 is present, fractions are given for material 0 (and material IDs < 0). Otherwise, these fractions are omitted.

The numerical part of VOLFR is a three-dimensional subdivision of space along material boundaries. The depth of the 3D binary subdivision is determined by L. Computer time requirements increase as a large power of L. Hint: use L = 2 or 3 initially and then gradually increase L until the numerical results are acceptable. When the subdivision equals L, then a volume exists containing more than one material. The fractional components of the volume are estimated with a ray-tracing technique. For each sub-volume containing more than one material, N x N rays are shot across the volume. The fraction of the ray going through each material becomes the corresponding estimate of the volume fraction of the material.