Boundary Layer Wind Tunnel
 
Power: 2 x 90 kW electric motors
Working section: 3.6m x 2.5m
Maximum speed: 20m/s
Features:
-3.6m diameter turntable
-Bike rig force balance
-Rolling road

The BLWT is a closed loop circuit wind tunnel. Wind is blown by two 1.8m fans down a diffusion section and passed through two mesh screens to remove turbulence before being speed up by a contraction for the test section. Large steel turning vanes are installed at each corner to increase the efficiency of the tunnel.

The test section is broken into three sections; a bike rig for measuring drag on cyclists, a rolling road for testing model car bodies and a large turntable for testing a variety of building scenarios. As the cyclists see apparent wind they don’t require any velocity profile and need very low turbulence. For this reason it is setup at the start of the section. In comparison boundary layer effects are very important for building testing, hence it is setup at the end of the test section.

The long test section allows the target atmospheric boundary layer to be simulated by adding roughness features or various shapes and sizes. This controls both velocity profile and turbulence levels.