The recirculating water tunnel is around 5000 mm long and 2200 mm high, whereby the test section is 1250 mm long, 333 mm wide and 250 mm high. The side wall and the basement plate of the test section are transparent for optical access. The tunnel is filled with 1.7 m³ water and is driven by an electric motor. The maximum flow velocity in the test section behind the nozzle with a contraction ratio of 4:1 is 1 m/s and the turbulence level is around 1 % .
The water tunnel is mainly used for qualitative flow visualisation experiments with ink and with tracer particles that are illuminated. The facility can be equipped with a PIV system for quantitative examinations. When synchronisation with an external event is required, PIV can be operated with a pulsed Nd:YAG laser, otherwise a continuous wavelength Argon-Ion laser is used.