Design and characterization of a low-speed aeroacoustic wind-tunnel research facility at IIT Kanpur

Abstract

This work presents the design and characterization of a state-of-the-art low-speed aeroacoustic wind-tunnel at Indian Institute of Technology Kanpur (IITK), which is a newly commissioned research facility for the experimental study of flow-induced noise generated from bodies placed in a flow field. This open-circuit, open-jet suction facility which is unique to IITK, is also the first aeroacoustic wind-tunnel in India. The facility is powered by large centrifugal fan of 75 KW rating which is controlled through a variable frequency drive. To achieve a low background noise, carefully designed parallel baffle mufflers (PBMs) are placed at the fan inlet and outlet. The inlet silencer is connected to lined diffuser and a bell-mouth collector which opens in a fully anechoic chamber made from metallic wedges, and its internal dimensions are 3.5 m × 3.5 m × 3 m. The chamber can provide a reflection-free environment beyond 250 Hz. A smooth contraction-nozzle of ratio 10:1 whose profile follows a fourth-order spline, and a settling-chamber with honeycombs and flow-screens is placed on the other side of the anechoic chamber. The test-section of size 600 mm × 600 mm is attached to the exit plane of the nozzle, and can provide flow speeds up to 45 m/s, where the maximum turbulence intensity was less than 1%.