Experimental investigation of a simulated compressor airfoil trailing-edge flowfield

Abstract

This study was motivated by the need for improved understanding of blunt trailing-edge compressor airfoil flow fields. The objective was to provide data that could be used to assist the development of computational procedures for predicting such flows. A large-scale, low subsonic Mach number, wind tunnel simulation of a compressor airfoil trailing-edge flow field was conducted using a flat-plate test model and laser Doppler velocimetry for flow field definition. Of potential importance in the numerical modeling of the flow was the finding that outer flow velocity profiles in the near wake were nearly identical, with viscous interaction effects confined to a region near the wake centerline having a thickness and length comparable to that of the trailing-edge thickness. Qualitative agreement with circular cylinder near-wake data and an observed lack of dependence of results on a change in plate boundary-layer thickness suggest that the flow is not strongly dependent on boundary-laye r thickness at separation. Periodic vortex shedding was encountered and shown to affect base pressure significantly. The associated strong transverse velocity fluctuations would be expected to be the dominant mechanism for mixing out the velocity defect in the initial wake region.