File:CSIRO ScienceImage 3742 Pye Laboratory Wind Tunnel.jpg

English: The special low-speed wind tunnel at CMAR's Pye laboratory allows scientists to undertake fundamental studies on how air interacts with the earth's surface. At this 'boundary layer', both smooth and turbulent flows are possible. The wind tunnel is driven by a powerful double-inlet centrifugal fan. Air is blown down the test section, enters the ambient space, and is then recycled. In detail, air flows from the fan through a coarse-flow straightener, a wide-angle diffuser with screens, a fine straightener, a settling chamber with screens, then a contraction, the working section, and finally the outlet diffuser. The working section is 1.8 m wide, 0.9 m high, and 16 m long. Several methods of air-speed control are available, providing high speeds for turbulent boundary-layer studies and very low speeds for experiments on flow over plants. The contraction ratio is 5.5:1, similar to that of a general purpose tunnel.