The Research on the Influence Law of Structural Parameters of Open Testing Section on Noise

Wind tunnel test sections are divided into two types: open test sections and closed test sections. Compared to closed test sections, open test sections are easier to install models, and due to the requirement of higher blockage ratio, open test sections are more suitable for large-scale models. However, at the same time, open test sections have the problem of flow field uniformity and higher noise levels in the test section compared to closed test sections. In order to address the issue of flow field noise in open test sections, a study was conducted on the influence of structural parameters on noise in the open test section. Based on the FD-12 wind tunnel test section, a scaled model was designed and wind tunnel tests were conducted at Mach numbers ranging from 0.5 to 1.2. By changing the structural parameters of the scaled open test section and measuring the fluctuating pressure values using pressure sensors, the influence of different structural parameters on noise in the open test section was obtained. The results showed that the length of the air collection chamber in the open test section had the greatest impact on aerodynamic noise in the test section, with longer air collection chambers resulting in lower noise levels. In addition, the study also measured the influence of other structural parameters on noise in the open test section and summarized the relevant influence rules. This study filled a gap in research on the influence of structural parameters on noise in open test sections at subsonic speeds and provided data support for the design of open test sections at subsonic speeds.