Investigation of the Noise Emitted by Pusher Propellers Installed on a Wing

What is it about?

Renewed interests in propeller driven aircrafts have recently arisen due to the need of increasing propulsion efficiency in the aviation sector. A pitfall in using propeller based propulsion systems is the increase of noise emissions, a critical issue in the case of highly integrated propulsion systems where complex flow-propellers-wing interactions occur. In this paper, noise emissions from a wing installed pusher propellers rig are investigated both experimentally and numerically. Aerodynamic and aeroacoustic measurements were carried out in an acoustically treated open test section Wind Tunnel. The experimental results provided the identification of optimal configurations in terms of noise impact. Numerical simulations comprised different wing-propellers configurations and flight conditions, reproducing test cases explored in the wind tunnel test campaign. It is shown that the numerical method is able to reasonably predict the noise installation effects and reproduce its sensitivity to the variation of relevant flight parameters.

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Photo by Timothy Newman on Unsplash

Photo by Timothy Newman on Unsplash

Why is it important?

The increasing demand in fuel efficiency in aviation has turned propeller-driven aircraft into an attractive solution to future air transport. This is the case of both standard aircraft configurations and more futuristic distributed propulsion-based configurations. The increased complexity in aircraft architecture related to the integration of such propulsion systems exacerbates aerodynamic installation effects for propellers. The purpose of the study was to identify an optimal configuration in terms of noise impact through a dedicated wind-tunnel measurement campaign and to validate the capability of a numerical model to predict tonal noise emissions for such a complex configuration.