The Relative Eddy in Axial Turbine Rotor Passages

It has been observed that strong radially outward flow can be present on the pressure surface of an axial turbine rotor blade. This paper demonstrates that the relative eddy plays a major role in producing this radial flow. An analysis of the relative eddy indicates that it can explain observed trends both with blade incidence as well as with spanwise location on the blade. Suggestions are offered as to how the turbine designer might exercise some control over this aerodynamic mechanism.