抄録
This paper presents experimental results on bypass transition of the boundary layer on the low-pressure turbine airfoil, and examines the sensitivity of this transition process to freestream turbulence and Reynolds number. Hot-wire probe measurements are performed on the suction side of low-pressure linear turbine blades at three Reynolds numbers and three levels of freestream turbulence conditions. The results of this experimental study show that the location of boundary layer separation does not strongly depend on the freestream turbulence level. However, as the freestream turbulence level increases, the size of separation bubble becomes small and the location of turbulent transition moves upstream. The size of separation bubble becomes small as Reynolds number increases. At freestream turbulence intensity of 1％, the velocity fluctuation due to Kelvin-Helmholtz instability is observed clearly in the shear layer of the separation bubble.
