The Hong Kong University of Science and Technology installed and commissioned the Ultra-quiet Noise Injection Test and Evaluation Device (UNITED). This facility is the first closed return anechoic wind tunnel in Hong Kong. The test section is enclosed within a 3.2 m x 3.1 m x 2 m anechoic chamber and it can be configured as an open-jet or closed-wall test section type. The cross-sectional area at the exit plane of the contraction section is 0.4 square meters, and the flow speed of the test section can be varied from 10 m/s up to 70 m/s. The facility possesses excellent flow and acoustic performance characteristics, and it has been used to study aerodynamics and acoustics of airfoils, wind turbine blades, duct acoustics, and rotor noise, to name a few.
