Experimental Analysis of Shear-Flow Effects on the Aerodynamics and Performance of a Propeller

In the field of helicopter aerodynamics, the proper characterization of the operational environment is essential in order to predict the interaction between the aircraft and the surrounding aerodynamic flow. This requirement becomes even more critical for multirotor drones, whose reduced dimensions make them more sensitive to atmospheric turbulence and velocity gradients. At the same time, the use of drones is rapidly expanding in sectors such as agriculture, civil engineering, logistics, and transportation, making a thorough understanding of the aerodynamic phenomena affecting their safety and performance increasingly necessary. This work focuses on the experimental analysis of the interaction between a small-scale propeller and two incoming flow conditions: uniform flow and shear flow. The experimental campaign was carried out in the indoor flight arena at Politecnico di Torino. The facility is equipped with a wind wall which allows us to generate controlled unsteady inflows. Using Particle Image Velocimetry we analyze the wake of a drone propeller and we evaluate its performances using a 6-axis load cell. The results include a detailed description of the wake, relevant for multirotor drone applications, and an evaluation of propulsive performance under different operating conditions. Data analysis allows quantification of the influence of shear flow on propulsive behavior and discussion of the main aerodynamic effects involved, highlighting key aspects and future research directions.