Experimental-Numerical Investigation Of The Aerodynamic Interaction Between Tandem Propellers Reproducing A Tiltwing Evtol In Transition Maneuver

Abstract

The present work investigates the aerodynamic interactions in a tandem propellers configuration during the transition manoeuvre, focusing on how the relative position and the propellers angle of attack influence the performance of the whole vehicle. The main objective is to broaden the available literature regarding eVTOL concepts, which as of today is primarily devoted to the analysis of pure cruise conditions. An experimental activity was performed with the aim of studying the interference effects through the comparison between the performance of a single propeller configuration and of the rear one in a tandem configuration, both in terms of load measurements and flow fields. A numerical analysis was performed by means of the mid-fidelity solver DUST to extend the experimental database and to provide further insights on the comprehension of the interaction effects produced on the rear propeller disk. In the perspective of a preliminary design phase, this work demonstrates that particular attention must be paid to the flight regime, since the free-stream velocity heavily affects the propulsive system behaviour. As a general outcome, higher vertical distances between propellers guarantee satisfactory performance despite the presence of mutual interference phenomena. Moreover, results analysis confirms the reliability and accuracy of DUST solver in the description of the complex propeller-propeller aerodynamic interactions mechanisms in this flight regime.