Design of a Low-speed Anechoic Wind Tunnel and its Aerodynamic and Aeroacoustic Performance

The Low-Speed Anechoic Wind Tunnel at Sun Yat-Sen University is a premier facility designed for experimental research on aerodynamics and aeroacoustics of aircraft scaled models or components. As a 3/4 closed-circuit wind tunnel with a contraction section nozzle dimension of 0.8 m × 0.6 m, it can be configured either as a closed test section or an open-jet section. The freestream velocity in the closed test section can be adjusted from 5 m/s to 80 m/s, while the openjet section ranges from 10 m/s to 70 m/s. The test section is enclosed within an anechoic chamber with dimensions of 5.5 m × 6 m × 3.5 m to ensure non-reflecting conditions. After the wind tunnel’s construction, comprehensive tests were conducted to evaluate its acoustical and aerodynamic performance. This paper presents the design criteria and characterization of the wind tunnel’s key components, along with the methods and results of benchmarking the flow quality and acoustic performance. This wind tunnel features exceptional flow quality with low turbulence intensity of 0.08% , 1% in the closed test section and open-jet section, respectively. The minimal level of background noise can attain a decibel level of 6.9 dBA under no-flow conditions, and at maximum flow velocity (70 m/s ) in the open-jet test section, the background noise reached 74.9 dB(A).The findings demonstrate that the aerodynamic and aeroacoustic performance indicators of the wind tunnel are comparable to similar facilities worldwide, positioning it as the leading aeroacoustic research facility in the Guangdong-Hong Kong-Macao Greater Bay Area at present.