A comparison of experimental and numerical results obtained for the secondary flow in a large turbine cascade

Laser Doppler anemometry has been used to measure the flowfield in a low-speed turbine cascade. The LDA technique successfully resolves the secondary velocity components associated with the formation of a strong passage vortex embedded in the blade suction-surface-endwall corner. The measured results are compared with numerical calculations made using a fully three-dimensional time-marching method which solves the inviscid equations of fluid motion. It is shown that good agreement could be achieved between the computations and the measurements, but only after ad hoc adjustment of the numerical viscosity terms. Nevertheless, it is suggested that until methods solving the viscous equations of motion are readily available, use of inviscid methods may provide a satisfactory approximation.