Slot film cooling downstream of misaligned plates

In a turbine engine,  an inter-platform gap often exists between the combustor and the turbine annulus because they are created as separate parts and assembled.  The gap must be supplied with leakage air to prevent ingestion of the hot combustion gases into the engines' interior. Moreover, misalignments often arise between the combustor and the turbine annulus due to their different thermal expansion and assembly tolerance. Herein, we present direct numerical simulation results of two misaligned plates with cross-flow and a leakage flow simulated as a slot jet. The study focuses on forward misalignment, backward misalignment, and plain configurations and reports the corresponding cooling effectiveness, flow statistics such as the turbulent fluxes and kinetic energy. Our results show that negative viscosity exists at regions where the incoming boundary layer starts to mix with the leakage jet and it takes time, or travel-distance, before the eddies in the incoming boundary layer and those in the leakage jet to come to an equilibrium, thereby favoring a transport Reynolds stress model over a local eddy viscosity type model.