Effects of Perpendicular Blade-Vortex Interaction, Part 2: Parameter Study

Experiments have been performed to document the turbulent flow produced downstream of an airfoil encountering an intense streamwise vortex. In the second part of two-part paper, measurements revealing the effects of blade-vortex separation, blade angle of attack, and vortex strength are presented. The purpose is to provide the data needed to improve blade-vortex and blade-wake interaction noise prediction schemes to account for these effects. A total of 48 flows were studied by measuring three-component velocity and turbulence stress profiles and spectra through the vortex core downstream of the interaction. Most measurements were made 15 chordlengths downstream of the blade trailing edge. These measurements show, consistent with an inviscid model, that the effects of the interaction are only weakly dependent on blade angle of attack and vortex strength and on whether the vortex passes to the suction or pressure side of the blade. The interaction has little influence on the properties of the vortex core for separations greater than about 0.3 chords