Aeroacoustic characteristics of single propeller-wing configuration

This paper presents the results of a detailed experimental investigation on the aeroacoustic characteristic of the single propeller-wing configuration in forward flight, including a comparison with an isolated single propeller. The results show that the wing has an effect on the propeller’s aerodynamic performance as well as noise production. The measurements were taken in the University of Bristol’s
aeroacoustic wind tunnel facility. The five-bladed propeller with a diameter of D = 9” and P/D = 1 was mounted in the centre of the NACA0024 wing to create a case where the wake from the propellers impinge directly on the wing to investigate the effects of propeller-wing interaction at various advance ratios, while maintaining a constant rotational speed of Ω = 8000 rpm. Aerodynamic and aeroacoustic measurements were conducted at fine increments of wind tunnel speeds ranging from 8 m/s to 24 m/s. The spectra and directivity of the far-field noise are studied in detail for broadband and tonal components. The results show that the wings influenced on the aerodynamic performance of
the propeller. A slight increase in the propeller’s thrust coefficient was observed for all advance ratios (J), which led to a 4% increase in overall efficiency, compared to the isolated case. Exploratory noise measurements indicate that the propeller-wing interaction leads to manipulation of the tonal noise at
blade passing frequency (BPF), contributing to variation in the directivity of the overall sound pressure level (OASPL) over the tested range of advance ratios, compared to isolated-propeller configuration. Understanding the propeller-wing interactions in single-propeller would help improve the design of next-generation multi-propeller Distributed Electric Propulsion (DEP) configurations.