The basic aerothermodynamic equations of turbomachine flow expressed with respect to nonorthogonal curvilinear coordinates and corresponding nonorthogonal velocity components are used to solve the compressible flow S1 surface in a turbomachine blade row with splitter vanes or tandem blades. The equation of stream function is solved by matrix technique, and the mass flow ratio and outlet flow angle are determined by applying the Kutta-Joukowsky condition to the trailing edges of the main blade and the splitter vane. Typical examples are given to illustrate the effectiveness of the present method.