Flow separation in blade cascades at off-design regimes of operation

Particular results from experimental aerodynamic investigation of blade cascades at extreme angle of incidence are presented. Data for modelling of off-design performance of machines are derived from simplified concepts on flow parameters in flow parts of turbomachines. Simulation of these complex conditions in the wind tunnel enables to observe and measure important flow structures and their development. An extensive flow separation is one of significant aerodynamic phenomena at extreme incidence angles of flow into blade cascades. Results of investigation prove considerable increase of coefficient kinetic energy losses at occurrence of flow separation. At high speed flows, transonic instability can set in. Unsteady phenomena are observed namely at extreme flow incidence conditions corresponding to considerable off-design performance of turbomachines