Boundary Layer Wind Tunnel

The Boundary Layer Wind Tunnel in the Hele-Shaw Laboratory within the Faculty of Engineering is a designated National Wind Tunnel Facility, supporting a diverse range of research activities for both academic and industrial applications. It serves fields such as fundamental and applied aerodynamics, aeroacoustics, environmental flow, air pollution, and wind engineering. This facility stands out for its “multi-purpose applications,” “modular construction,” and “versatile operation”—core principles that shape its design capabilities.

The tunnel spans 30 meters in length and is driven by nine axial fans with a combined output of 240 kW. This multi-fan setup can operate in either partial or full configurations, allowing steady flow velocities between 0.5 m/s and 35 m/s, with exceptionally low turbulence intensity. The test section, measuring 2 meters in width, 1 meter in height, and approximately 18 meters in length, ranks among the largest available at UK universities. It can generate a naturally developed boundary layer over 25 cm thick (Re_τ ≈ 10,000). Even thicker boundary layers are achievable using custom-designed surface roughness elements and spires tailored to the wind tunnel setup.

The wind tunnel is equipped with a fully automated tracer gas injection system, capable of onsite blending and the simultaneous release of multiple streams of mixed specialty gases, including hydrocarbons (e.g., propane, butane, ethane) and inert gases (e.g. argon, nitrogen, helium). For concentration measurements, techniques such as gas chromatography-mass spectrometry and fast flame ionization detection (FID) are employed. These can be integrated with PIV, hot-wire CTA, and highly instrumented models, enabling a broad range of fundamental and applied research in scalar dispersion. Currently, the facility is used for air quality assessments in various cities across the UK and Europe, as well as for foundational studies on topics such as the effects of building layouts and terrain on pollutant dispersion, and indoor-outdoor pollutant fluxes.

Notable features of the facility include boundary layer suction control and tilting ceilings with adjustable pressure gradients. The wind tunnel is outfitted with extensive measurement capabilities, including a large (100+ channel) beamforming array and data acquisition systems, time-resolved PIV, static and dynamic pressure sensors, a drag plate, infrared thermal imaging, high-speed schlieren imaging, and Kevlar walls, among others.