The mesh in Figure 26.8.2 was created for computing a turbulent jet. Local refinement was used in TGrid to create a mesh that is fine in the region of the jet, but coarse elsewhere. This created a very sharp change in cell volume at the edge of the jet.
To improve the mesh, it was refined using volume adaption with the criterion that the maximum cell volume change should be less than 50%. The minimum cell volume for adaption was also limited. The resulting mesh, after smoothing and swapping, is shown in Figure 26.8.3. It can be seen that the interface between the refined region within the jet and the surrounding mesh is no longer as sharp.