Suction side micro-riblet patches for a turbine airfoil

A gas turbine engine, comprising:

• a first turbine airfoil defining a pressure side surface;
• a second turbine airfoil defining a leading edge, a trailing edge, and a suction side surface extending therebetween, wherein the pressure side surface of the first turbine airfoil and the suction side surface of the second turbine airfoil define a flowpath therebetween, wherein a throat line is defined along the suction side surface, the suction side surface comprising:
• a plurality of micro-riblet patches defined along the suction side surface aft of the throat line, wherein each micro-riblet patch of the plurality of micro-riblet patches extends in a flow-wise direction between the throat line and the trailing edge, wherein at least one micro-riblet patch of the plurality of micro-riblet patches includes at least two inner riblets extending at a first flow-wise length and at least two outer riblets extending at a second flow-wise length, wherein the first flow-wise length is greater than the second flow-wise length, wherein the at least two inner riblets are disposed spanwise between the at least two outer riblets.