Design and performance of a small-scale aeroacoustic wind tunnel

The D5 aeroacoustic wind tunnel at Beihang University is a newly commissioned small-scale closed-circuit wind tunnel with low turbulence intensity and low background noise. The wind tunnel is built to study both aerodynamic and aeroacoustic performance of aircraft components or scaled models. The wind tunnel has two types of test sections, the closed type test section is used for aerodynamic tests while the open type test section is mainly used for aeroacoustic experiments. Both types of test section are 1 m in height and 1 m in width, and the maximum wind velocity in the test section can be up to 80 m/s. An anechoic chamber is built surrounding the test section to provide the non-reflecting condition. This paper provides an overview of design criteria and performance of the small-scale wind tunnel. The layout of the wind tunnel and some critical design treatments to improve aerodynamic and acoustic performance are discussed in detail. Some experiments are conducted to verify the performance of D5 wind tunnel, results confirm that the turbulence intensity is less than 0.08% in the core of test section and the background noise is comparable with other aeroacoustic wind tunnels. A scaled simplified nose landing gear model is also measured as a benchmark test, results reveal that noise radiated from the model is adequately higher than the background noise for a wide frequency range and remarkably consistent with other results from literatures.