Numerical Predictions of Wake-Induced Transition in a Low Pressure Turbine

A bypass transition model has been included in a Quasi-3D, blade-to-blade, unsteady, viscous solver to investigate the possibility of predicting wake induced effects on LP turbine blade boundary layers. In the present work, transition criteria derived from the Abu-Ghannam and Show, and Mayle models were implemented in conjunction with an algebraic turbulence model based on the mixing length concept. Unsteady analyses were then carried out on a three stage LP turbine. Details of the unsteady boundary layer transition under the effects of the passing wakes will be presented and discussed for both stator and rotor blades. The different transition patterns arising from the boundary layer interaction with multiple incoming wakes in subsequent blade rows will also be investigated.