Past research effort on gas turbine technology has focused on reducing loss generation and cooling flow requirements in the main flow path. To further improve turbine efficiency and durability, the secondary air flow system, critical to operation of these engines, needs to be investigated and its associated loss mechanisms reduced. This project aims to determine the specific drivers that set the loss generating mechanisms and heat transfer in the secondary flow system. Understanding of these drivers would allow the formulation of strategies for turbine performance and durability enhancement to benefit the next generation of large industrial gas turbines for power generation. The project seeks to address, on a quantitative basis, the following: 1) the effects of the cavity on the aerodynamics of and characteristic turbine operating parameters in the blade-tip region; 2) response of the blade tip shroud cavity flow to injected cooling and seal leakage flows and turbine tip configurations; 3) the role of unsteadiness on the tip shroud cavity flow and the associated loss generation; and 4) the impact of (1) and (3) on overall multistage axial turbine performance including the downstream diffuser. Once the aerodynamic loss generation mechanisms have been isolated, heat transfer will be incorporated to determine its effect on the turbine tip shroud cavity flow.