Modelling of supercritical turbulent flow in an open channel with transversal ribs on its bottom was concentrated particularly on the development of flow separation behind ribs and on the corresponding changes of free surface. Further, the pressure drag of individual ribs was investigated including its dependence on the rib spacing, as well as the origin of secondary flow near the side walls of the channel behind ribs. Numerical results obtained by the software ANSYS CFX 11,0 were compared with experiments carried out by means of LDA and PTV techniques in free-surface water experiments carrid out by means of LDA and PIV techniques in free-surface water channel 200 x 200 mm with one or two transversal ribs 10 x 10 mm with various spacing. and Obsahuje seznam literatury