Environmental Flow (EnFlo) Laboratory

The Environmental Flow (EnFlo) Laboratory hosts various fluid mechanics research and teaching facilities, including a world-leading meteorological wind tunnel, several other wind tunnels and a fully-automated laboratory measurement instrumentation suite.

Overview

Established in 1993 with funding from EPSRC, National Power, the UK Meteorological Office and the ��ý, EnFlo is an internationally recognised centre of excellence in atmospheric boundary layer flows and environmental aerodynamics.

The lab is home to a large and unique facility, the EnFlo boundary-layer wind tunnel, which is the only one in the UK capable of simulating wind characteristics in non-neutral conditions, including stable and convective (unstable) boundary-layer flows. It hosts two other large conventional wind tunnels and a series of smaller wind tunnels for testing, instrument calibration and teaching purposes.

Measurement capabilities include 3-component velocity and turbulence, mean and fluctuating tracer concentration, pressure and temperature, forces and moments.

Wind tunnels

EnFlo Wind Tunnel

This wind tunnel is EnFlo's main facility and it is also part of the . At 20 metres long it features a comprehensive inlet flow and surface heating and cooling systems for generation of neutral, stable and unstable boundary layers and neutral and stable free flows.

Other key features include two three-dimensional, computer-controlled traversing gears, tracer supply systems, calibration facilities, a turntable and extensive condition monitoring. The tunnel and all associated capabilities operate under full computer control, enabling prolonged unmanned operation.

Specifications	Thermally stratified Open circuit, twin fans, suck through
Dimensions	Working section: 20L x 3.5W x 1.5H m Overall length: 27.2 m
Air speed range	0.5 to 5.0 m/s
Inlet heater	Number of layers: 15 at 0.1 m spacing Maximum heating rate: 400 kW Maximum temperature gradient: 80 °C/m Maximum bulk temperature rise: 80 °C
Roof/floor panel performance	Maximum heating rate: 2 kW/sq. m Maximum surface temperature: 120 °C Maximum cooling rate: 1 kW/sq. m Minimum surface temperature: 5 °C
Side panel performance	Number of heating zones: 3 at 0.5 m Maximum heating rate: 0.2 kW/sq m

Aero Tunnel

A 1.1 x 1.4 m test-section recirculating (closed-loop) wind tunnel facility with maximum speed of 40 m/s, featuring a rolling-road capability, full (nonintrusive) floor-to-ceiling, fully-automated particle-image velocimetry and laser-Doppler anemometry scanning capability, a six-component force balance, a five-axis traversing system and a suite of other fully-automated instrumentation systems for quick-turnaround, high-yield experimental testing, including a static test rig to prepare models.

Specifications	Closed circuit Rolling road and boundary-layer suction
Dimensions	Working section: 9L x 1.1W x 1.4H m
Air speed range	5 to 40 m/s

‘A’ Tunnel

A 0.9 x 0.6 m test-section open circuit wind tunnel facility with a free-stream turbulence intensity <0.1%, used primarily for rapid testing, calibration and validation.

Specifications	Open circuit, blow down Low-cost facility Free-stream Turbulence Intensity <0.1%
Dimensions	Working section: 5L x 0.9W x 0.6H m
Air speed range	3 to 30 m/s

Other wind tunnels and smaller rigs

The EnFlo lab features several other smaller rigs (small wind tunnels, water tanks, bench-sized facilities), including:

‘C’ Tunnel	Open circuit, blow down Working section: 0.3 x 0.3 x 3 m (width x height x length)
‘D’ Tunnel	Open circuit, blow down Working section: 0.6 x 0.3 x 2 m (width x height x length) Maximum wind speed: 20 m/s

Available instruments and services

Force measurements (6-component force balances)
A wide range of pressure sensors and post-processing capabilities, including low-speed measurements
3-D laser Doppler anemometry (LDA)
Multiple 2-D and 1-D laser Doppler anemometry systems
Hot-wire (and X-wire) anemometry
Tracer concentration measurements, including fast response instruments (>200 Hz) by means of fast-response Flame Ionisation Detectors (FFID)
Stereo particle image velocimetry (PIV)
A wide range of flow visualisation capabilities.