Acoustic and aerodynamic evaluation of POLIMI tandem propellers configurations within GARTEUR AG26

Abstract

The present work describes the activities performed in the GARTEUR Action Group HC/AG-26 to study the acoustic and aerodynamic characteristics of tandem propellers configurations, with a focus on the effects of mutual interactions between propellers typical of eVTOL aircraft. In particular, this paper describes comparisons between numerical activities and experimental results obtained over a dual propellers test case developed by Politecnico di Milano. The investigated configurations included both hover and airplane- mode flight condition with overlapping between propeller disks. Numerical results obtained by the partners simulations based on aerodynamic solvers characterised by different levels of fidelity from panel methods to CFD are compared to experimental results and discussed. Results comparison highlighted the capabilities and limits of the different numerical approaches to reproduce a quite challenging test case characterised by an high degree of unsteadiness due to propeller-propeller aerodynamic interaction and robust viscosity effects. Numerical predictions reproduce correctly the trends in aerodynamic parameters and changes in overall sound pressure level due to lateral shifts between propeller axis.