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Three-dimensional flow simulations through a turbine cascade were carried out for an exit isentropic Mach number of 0.79 and a Reynolds number of 2:8 Â 10 6 . The main objective is to increase the base pressure. Calculations were carried out using an in-house numerical code, where a 2nd order Roe's flux-difference splitting for inviscid numerical fluxes, a 2nd order implicit dual time method for time integration, and Delayed Detached Eddy Simulation for turbulence were employed. The present idea to increase the base pressure is to connect the pressure and suction sides of the blade using microtubes distributed uniformly along the span on the trailing edge. Simulated results show that this modification does not affect the blade load, increases the base pressure by 0.7%, and decreases the overall loss by 3%.

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Trailing edge vortex shedding from a turbine cascade was numerically simulated for an exit isentropic Mach number of 0.79 and a Reynolds number of 2:8 Â 106 . The objective of this study is to clarify the time evolution of the vortex shedding process from a turbine blade and the mechanism of energy separation appearing in the wake. Calculations used a locally developed numerical code, employing a second-order AUSM scheme for inviscid numerical fluxes, a secondorder implicit dual time method for time integration, and Detached Eddy Simulation for turbulence. Calculated results confirmed a non-uniform pressure distribution along the trailing edge, which was observed experimentally and different from a uniform distribution at low subsonic Mach number. The energy separation where instantaneous total temperature splits into hot and cold spots in the wake is caused by convection and vortex rotation. In addition, the formation and dissipation phases of vortices affect the energy separation.