This paper presents a study of the three-dimensional e owe eld within the blade rows of a single-stage highpressure axial turbine (low-speed, large-scale ). Measurements have been performed in the stationary and rotating frames of reference. Time-mean data have been obtained using e ve-hole pneumatic probes. The transport mechanisms of the stator wake and passage vortices through the rotor blade row have been studied using smoke e ow visualization. Furthermore, unsteady measurements have been carried out using a three-axis hot wire. Steady and unsteady numerical simulations have been performed using a structured three-dimensional Navier ‐Stokes solver to further understand the blade-row interactions. The transport of the stator viscous e ow through the rotor blade-row is described. The rotor passage vortices are affected by the transport of the stator secondary e ow. It is observed that the stator secondary e ow vortices are convected through the downstream rotor blade-row in a similar but not identical way to the wake. At the hub the kinematic interaction between the stator and the rotor passage vorticeshas two effects. First,thesuction sideleg of the statorpassagevortex isdisplaced radially upwards over the developing rotor passage vortex at the hub. Additionally, the pressure side leg of the stator passage vortex is entrained into the rotor passage vortex. The predicted e owe eld was interrogated from the perspective of loss production. The contribution of the unsteady e ow to the stage loss has been evaluated using unsteady numerical simulations. The effect of stator viscous e ow transport on the rotor e ow angles is also discussed in brief. Finally, a kinematic model is proposed for the transport of the secondary-e ow vortices in the downstream blade-row based on the understanding obtained from the measurements and numerical simulations.