Grid adaptation is a very powerful tool for optimizing CFD calculations. Unfortunately the typical isotropic adaptation used for 3D flows may result in excessive number of elements. The reason for this is that during refinement of the grid around, e.g. the shock wave the grid cells becomes smaller uniformly in all directions. It means that after splitting N cells in the direction normal to the shock wave the number of the cells will be increased to N K 3 (K describes how many new edges are created after splitting an old one - if an edge of a cell is split into two edges then K = 2). When the anisotropic adaptation is used the grid is refined only in the direction normal to the shock wave and the number of the cells would be increased to N K.