This paper presents an advanced approach to compute the three-dimensional,
rotational, adiabatic, inviscid flow of a perfect gas in a highly twisted transonic axial turbine
stage. The time-dependent Euler equations, expressed in a Cartesian coordinate system, are
solved using a time marching method and a finite volume approach. The absolute flow is
computed in the nozzle vanes passage, whereas the relative flow is computed in the rotor
blades passage. The phase relation of nozzle and rotor flows and the related blade row
interaction are accounted for in the time-space domain. The results show that the present
method of calculation makes a practical contribution to predict actual turbine flows through
a turbine stage that have an arbitrary number of vanes and blades for each nozzle and rotor.
It is clear that this flow has a three dimensional aspects, in spite of the high hub/tip ratio
which has theoretically a two-dimensional flow aspects.