e-mosty September 2017: Mersey Gateway Bridge. Arenales Bridge. Mersey Gateway Bridge. Arenales Bridge. BLWT. - Page 39

The air flow is supplied by two axial fans Ø1600 powered by asynchronous motors 2 x 75 kW with frequency changers feed they supply the flow air capacity above 100 m 3 /s by max 1000 rpm. It is also possible to use very low velocities that investigate the flow and diffusion of toxic or radioactive agents in the scales 1:1000 to 1:1500 under the condition of validity of Froude number. The tunnel is equipped with two reference sensors – Prandtl sensors (Pitot static tubes) for assessment of dynamic air pressure and measuring the overall and static pressure. Differential pressure sensors are also available for monitoring of wind pressure distributions on models. Pressure sensors transfer pressures to electric quantities which are compiled and saved in a computer; next they are processed using the LabView software. Saved data can be used in the next investigations or they can be shared with tunnel control systems for governing the air flow velocity settings in tunnel. Devices:   Digital ALMEMO device with probe type FVAD 35 TH5K2 Three 16-channels pressure scanner type Scanivalve DSA3217/16 (measuring range up to 2.5 kPa)  CTA (Constant Temperature Anemometry) - an anemometer with heated wire is a proper device, working on the principle of King's cooling law. CTA is used for measuring velocity in a point and continuously provides information on the velocity in time series. Presently the BLWT tunnel is equipped with Mini CTA Type 54T42, sufficient for simple experiments.  20 Irwin probes - simple omni directional sensors for wind-tunnel studies of pedestrian level winds. Figure 1: Positions of measuring devices Figures 2 + 3: View on moveable arm and anemometer probe 3/2017