Turbine airfoil arrangement incorporating splitters

A turbine apparatus, comprising:

• a turbine rotor stage including a disk rotatable about a centerline axis, the disk defining a rotor flowpath surface, and an array of axial-flow turbine blades extending outward from the rotor flowpath surface, the turbine blades defining spaces therebetween;
• a turbine nozzle stage comprising at least one wall defining a stator flowpath surface, and an array of axial-flow turbine vanes extending away from the stator flowpath surface, the turbine vanes defining spaces therebetween;
• and
• wherein at least one of the rotor or nozzle stages includes an array of splitter airfoils extending from at least one of the flowpath surfaces thereof, the splitter airfoils disposed in the spaces between the turbine blades or turbine vanes of the corresponding stage, wherein the splitter airfoils have a thickness ratio which is less than a thickness ratio of the corresponding turbine blades or turbine vanes.