The performance of an ultra-high-lift after loaded low pressure turbine (LPT) at steady and unsteady state has been investigated experimentally in the present paper. The experiment result show that both of the separation bubble and profile loss have been decreased by the wakes induced transition combined with the separation transition at low inlet Reynolds number and low inlet free stream turbulence intensity under the effect of upstream wakes. In one wake passing periodicity

the boundary layer separation is expanded and shrunken periodically due to the upstream wakes. It has also been seen that the wake is cut into 2 parts-a primary wake and a secondary wake

downstream the blade maximum camber. Even though the secondary wake can induce the transition

the suppression effect of separation is low due to the low wake intensity.