Abstract: A turbomachinery apparatus includes: a turbine, including: a turbine component defining an arcuate flowpath surface; an array of axial-flow turbine airfoils extending from the flowpath surface, the turbine airfoils defining spaces therebetween; and a plurality of fences extending from the flowpath surface, in the spaces between the turbine airfoils, each fence having opposed concave and convex sides extending between a leading edge and a trailing edge, wherein the fences have a nonzero camber and a constant thickness, are axially located near the leading edges of adjacent turbine airfoils, and wherein at least one of a chord dimension of the fences and a span dimension of the fences is less than the corresponding dimension of the turbine airfoils.