Wind Engineering Facilities

Wind Engineering Services has four wind tunnels located within the Department of Civil Engineering:

Test section: 2.0 m x 2.4 m; fetch: 20 m
Maximum wind speed: 16 m/sec in the boundary layer section

The No.1 Boundary Layer Wind Tunnel is an open circuit wind tunnel used within the department for research, consulting, and teaching activities. The atmospheric boundary layer test section is uniquely suited for the study of wind induced building pressures, building motion, and pedestrian wind climates. The blockage tolerant section also allows detailed assessment of complex topographic areas (e.g. analysis of wind turbine placement). The tunnel is equipped with variable levels of fetch roughness so site specific turbulence characteristics can be simulated.

Test section: 1.2 m x 1.5 m; fetch: 4.5 m
Maximum wind speed: 12 m/sec

The No.2 Boundary Layer Wind Tunnel is an open circuit, open test section wind tunnel primarily used for teaching and fundamental research purposes. The open test section allows testing of larger models without the need for any blockage corrections. The fetch roughness characteristics can be varied to simulate variable terrain categories. The tunnel is also able to be run with no roughness features making it suitable for testing individual features, e.g. roof fitted solar panels.

Impinging air jet: 0.31 m diameter
Maximum wind speed: 20 m/sec

The impinging air jet is primarily used as a research tool for studying the velocity and pressure fields associated with the impingement of an air jet on a solid surface. The impinging jet facility has a variable outlet velocity, variable jet to board distance, and a variable jet/board incidence angle. The impinging jet can be run as either a steady or pulsed air jet allowing researchers to study temporal characteristics associated with gusts during thunderstorm outflows. The impinging jet also provides experimental results used to help validate more complex numerical models.

Test section: 0.6 m x 0.9 m; fetch: 4 m
Maximum wind speed: 6 m/sec

The Snowdrift Wind Tunnel is a closed circuit wind tunnel with sodium bicarbonate (baking soda) used for snow simulation. The snowdrift wind tunnel can be used to model wind driven snow deposition patterns around simple and complex structures giving temporal and spatial prediction of snowdrift patterns. Sodium bicarbonate is used for scaled snow particles due to its density, compaction and angle of repose properties. The snowdrift wind tunnel is used for research and consulting activities and has been used in modelling drift patterns in the Southern Alps region of Australia, and Antarctica.

Modelling snowdrifts around Antarctic structures in our snowdrift tunnel

Within the Wind Engineering facility a number of different instruments are used for measuring and understanding the behaviour of wind in and around buildings. Instruments are also required for predicting and measuring the response of buildings to the wind. Several of our instruments with example applications are listed below.

Wind tunnel instruments

• High frequency pressure scanning system – up to 254 pressure taps can be simultaneously scanned for measuring façade cladding pressures or for integrating pressures over the face of a structure.
• High frequency base balance – used for determining overall structural loads applied to a buildings foundations or supports. Knowledge of the dynamic properties of a building allows a prediction of structural responses.
• Aero-elastic strain gauge systems – used for highly wind sensitive structures where mode shape predictions are not adequate and structural response must be measured by fully modelling a building’s structural characteristic.
• Thermal anemometers (hot-wires) – used to measure the wind velocity at different locations in the wind tunnel. The miniature size and multi-directionality of hot-wires makes them ideal for pedestrian/environmental comfort testing.
• Cobra probe – used for quick and accurate velocity profile measurements, the robust and easy use of this instrument makes it invaluable to our thunderstorm downburst research.
• Flow visualisation system – a high quality tracer smoke generator along with a video recording system allows an enhanced understanding of the wind flow in complex experiments.

Full-scale measurement instruments

• Accelerometers – used to measure the dynamic properties of any structural system such as natural frequency and damping.
• Anemometers – used to measure wind speed and direction. Currently some of our anemometers are mounted on the top of buildings in Sydney and monitoring the temporal characteristics of thunderstorms that pass over Sydney.

A building model for a wind tunnel test