Abstract: A turbine blade including an airfoil section having contoured surface geometries between the consecutive ribs or turbulators on the leading edge passage walls is described. The contoured surface geometries increase the overall heat transfer surface area between adjacent ribs as compared to the heat transfer surface area of a smooth inter-rib wall. The contoured surface geometries do not, however, change the overall serpentine passage geometry or the large scale flow characteristics of the turbulated cooling passageways. The contoured surface geometries may have many different geometries (e.g., triangular, conical, semi-cylindrical, cylindrical columns or indentations in the side wall such as semi-circular dimples).