Isolated propeller aeroacoustics at positive and negative thrust

Using propellers in negative thrust conditions can potentially result in many benefits, such as a steeper descent, a reduced landing run, reduced community noise, energy regeneration, etc. However, the aerodynamics and aeroacoustics of propellers in this regime are not well understood. This paper presents an aeroacoustic analysis of an isolated...

Aerodynamic interaction between propellers of a distributed-propulsion system in forward flight

This article describes an experimental investigation of the aerodynamic interaction that occurs between distributed propellers in forward flight. To this end, three propellers were installed in close proximity in a wind tunnel, and the changes in their performance, flow-field characteristics, and noise production were quantified using...

Aerodynamic and Aeroacoustic Interaction Effects for Tip-Mounted Propellers: An Experimental Study

Propellers can enable a significant reduction in energy use of future aircraft by offering a higher propulsive efficiency than turbofan engines. This is especially relevant for a new generation of (hybrid-)electric aircraft. However, the integration of propellers with the airframe remains a challenge, and leads to performance and noise penalties...