A gas turbine engine includes an inner shaft extending axially along the gas turbine engine, a plurality of disks extending radially inwardly and toward the inner shaft, at least one hole in at least one of the plurality of disks, and an obstruction positioned between the inner shaft and an end of the disk having the at least one hole, such that a bore flow that flows along an axial length of the inner shaft is obstructed from flowing along the shaft by the obstruction, and forced to flow radially outward from the obstruction, through the at least one hole, and radially inward toward the inner shaft.