### 10.9.21. Parts - Zoning - Refine

This window lets you refine structured Lagrange, ALE, Euler-Godunov and Euler-FCT parts. However, the part must satisfy the following requirements in order to utilize this new refining facility:

- The part must be a 'box' type object.

- The X, Y, and Z coordinates of the grid nodes must increase with the I, J, and K indices respectively.

I/J/K Factor

Enter the Refine Factor for the I/J/K index; that is, number of the new cells created from an original single cell in that direction.

The refining algorithms are by default applied to all cells within a part. In order to limit the range of cells within a part that undergo refinement, you can select an appropriate IJK-RANGE first. In addition it should be noted that the following limitations apply to the refinement of Euler and ALE parts.

- For simplicity with multi-material Euler-Godunov grids, the material volume fraction of an original cell is assigned to all the new cells created from that original cell. Thus the material interface on the new grid may not be exactly the same as that on the original grid.

- For ALE grids, the original motion constraint of the ALE nodes is not retained during the refining procedure. The motion constraint for all the new nodes is set to Lagrange, even if the constraint of the original node is, for example, Equipotential. You will therefore need to redefine the motion constraints for ALE parts following the refining process.

The cell index for time history gauge points is also updated during the refinement. Furthermore, the mass is always conserved between the original and refined parts. However, the momentum and kinetic energy in Lagrange and ALE parts may not be conserved exactly because the mesh refinement modifies the nodal masses and thus affects the momentum and kinetic energy calculation. For Euler-Godunov and Euler-FCT parts, since the cell mass is used to calculate both the kinetic energy and momentums, refinement does not affect the calculation. The kinetic energy and momentums should therefore always be conserved.

An example of the refinement of a Lagrangian part is shown below. Note that the refinement factors IFACT, JFACT and KFACT have been set to 1, 2 and 3 respectively.

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