Tip-Leakage Flow: a Detailed Simulation with a Zonal Approach

Abstract

The secondary flow generated by the clearance between an isolated airfoil tip and anend-plate is analyzed by means of a zonal large-eddy simulation, in comparison with avail-able experimental data. The flow around the tip clearance is described with full large-eddysimulation, while Reynolds-averaged Navier-Stokes is employed in the rest of the compu-tational domain in order to limit computational cost. The various analyses of the flowcharacteristics (mean velocities, Reynolds stresses, spectra) show a very good agreementbetween the experiment and the simulation. Looking at the mean velocities, an intensetip-leakage vortex is observed on the suction side. The Reynolds stresses are used toevaluate the anisotropy of the vortex. Finally, the spectral content is investigated in thenear-field and the far-field, and the leakage flow is shown to be characterized by a dominantcontribution in the range [0.7 kHz; 7 kH z].