An Experimental Investigation of Boundary Layer Ingestion and Aerodynamic Interactions*

This study experimentally examines the aerodynamic interaction between a rotor and turbulent boundary layer. The fundamentals of this research are directly relevant to various applications, including over-the-wing propellers (aeronautics) and propeller-hull interactions (marine). The experiments are performed in the boundary layer wind tunnel (1.2m x 1m cross section) located at the University of Southampton at downstream location of 7.5 m from the beginning of the test section. A smooth-wall boundary layer develops over the bottom wall of the wind tunnel with a boundary layer thickness of 10 cm. A two-bladed 16-inch diameter propeller is installed in the wind tunnel such that the distance between the rotor and the wind tunnel floor could be altered. This enables us to examine the effect of tip-gap on the propeller/BL interaction. Phase-locked low-speed high-resolution stereoscopic particle image velocimetry is performed to examine the downstream development of the tip vortices generated by the propeller and its interaction with the boundary layer. We will present results where the evolution and the decay of the tip vortices ingested in the boundary layer are compared to tip vortex characteristics of a rotor in isolation (i.e., the rotor is outside of the boundary layer).