Abstract: A bypass channel for use in an inter-turbine transition duct assembly of a turbine engine is connected to a suction port disposed upstream of a high-pressure turbine and at least two injection openings disposed downstream of the high-pressure turbine. The flow through the bypass channel is motivated by the natural pressure difference across the high-pressure turbine. The flow out of the at least two injection openings is used to energize the boundary layer flow downstream of the high-pressure turbine in order to allow for the use of a more aggressively expanded inter-turbine duct without boundary layer separation. Methods for optimizing the flow through the turbine engine are also disclosed.