Tip Vortex Dynamics of a Pitching Rotor Blade Tip Model

Abstract

The tip vortex of a finite wing undergoing dynamic pitch oscillations is investigated by means of an experimental wind tunnel study. The motion and flow parameters as well as the model geometry were adapted to rotorcraft applications, including test cases with fully attached flow, light stall, and deep dynamic stall. High-speed Particle Image Velocimetry was used to study the spatio-temporal behavior of the tip wake at different streamwise positions. Combined to surface pressure measurements, the data establishes a connection between the sectional lift of the model and vortex parameters (trajectory, core radius, circulation, etc), including dynamic phenomena like hysteresis and vortex breakdown during stalled flow conditions.