circulating water tunnel

The ZARM Circulating Water Tunnel is continuously driven and consists of a horizontal test section, a closed main circuit with axial driving impeller and a secondary circuit with a rotary pump system for degassing and filtering the water, in order to keep it optically clear. To reduce the turbulence level within the circuit and smooth the velocity distribution especially in the test section a combination of a honeycomb and two screens is used. Typically turbulence levels of Tu < 0.7% can be achieved. Large PMMA windows in the test section allow to observe the models from all sides. The facility can be run in different operation modes with free surface or as a closed tunnel to investigate effects of cavitation. Flow velocities are infinitely variable in a wide range of up to 15 m/s. The used fluid of about 6000 l water is mixed with tracers (glass spheres with diameter of d= 10 µm and density of r = 1000 kg/m³) of a 0.01% concentration of the tunnel volume. In most cases the models are mounted internally on a turnable gauge from back or the top; the angle of attack is adjusted from outside. A sting attachment on the central turnable offers alternative support.

Further Information on the Circulating water tunnel will be found on the following pages: