Mathematical simulation of disk levitation and rotation

The problem under discussion is about levitation when gas flows in narrow space between two horizontal disks. The upper disk is lifted and rotated by gas flow (Mach number $M\ll1$), The lower disk has spiral grooves. The grooves cause rotation of gas flow and, consequently, rotation of the upper disk. A two-dimensional equations for gas parameters averaged in split have been obtained. One can receive frequency of rotation and height of the upper disk lifting from this equations. The algorithm of numerical solution of the obtained equations and the results of calculations are given in the article. Comparison with experimental results has been done.