Development and Validation of a Small-Scale Anechoic Wind Tunnel

After more than half a century of intense activity and the considerable development of complex numerical models, aeroacoustic research still relies heavily on experimental approaches. Experiments are essential to provide reference data for fundamental test cases, to understand highly complex and interacting phenomena, and to validate numerical simulations. At the University of Adelaide, the School of Mechanical Engineering is undertaking the upgrade and optimisation of its small-scale wind tunnel to support its increasing research activity in aeroacoustics. An experimental programme to start in 2007 requires a quiet 75 x 300 mm2 rectangular cross-section jet with a maximum flow speed of 30 m/s, in an enclosure that is anechoic at frequencies above 200 Hz. This paper gives a brief outline of the process followed to upgrade the wind-tunnel, including the air supply system, flow treatment and jet cross-section. Additionally, the flow properties and acoustic performance of the wind tunnel are assessed through a series of validation experiments, and the main results are presented here against the initial design objectives. The results of a simple experiment consisting of a cylinder in cross-flow are also presented, and initial results are compared with a semiempirical model to demonstrate the performance of the wind tunnel. Finally, a brief outline of the subsequent research work to be carried out in the wind tunnel is given.

Damien Leclercq, Con Doolan and Jochen Reichl