Low Subsonic Wind Tunnel - Design and Construction

This paper describes the design and the construction details of a medium size subsonic low-speed wind tunnel, which has been designed to achieve 90 m/s in the working section with expected low intensity turbulence level, making it available for researching in areas such as low speed aerodynamics (flight and terrestrial vehicles), sport activities, civil engineering applications, fundamental research in Fluid Mechanics and other possibilities. To accomplish such objectives a very detailed design was carried on using theoretical analyses, CFD simulations and semi-empirical methods, all of them applied to improve the flow quality along the wind tunnel sections. A very careful attention has been focused to the design of the fan blades and the electrical engine assembly, which has been inserted in a "pusher" configuration. Flow control and stabilization also took place using screens, honeycombs and corner vanes, all of them optimized to induce low turbulence levels in the working section. The design and construction of each wind tunnel section has been presented and discussed shedding light to the most relevant technical aspects and an attempt is made here to present some design and manufacture guidance for the main components of a low subsonic wind tunnel.