Design of a variable Mach number wind tunnel nozzle operated by a single jack

This paper presents the detailed design process of the variable Mach number nozzle operated by a single jack, and then a design case that covers a Mach number range of 1.5 to 2.0 is investigated. The computational fluid dynamics (CFD) approach is employed to obtain the flow quality of the test area at different operating conditions. The results show that the elastic deflection of the flexible plate can be calculated using the boundary conditions associated with the traditional nozzle design method. The flexible plate length affects the flow quality of the test section significantly and is set at 560 mm in the current study, corresponding to the variable thickness coefficient of 1.213. In addition, the standard deviation and flow angularity of the working section throughout the Mach number range can satisfy the requirements of the National Military Standard of China, which indicates that the design method of the single-jack nozzle is feasible.