The towing channel was developed in 2002 to facilitate research projects focused on the interaction between moving objects and the seabed. This includes a wide range of applications such as the effect of trawling gear components on the seabed; pipeline–seabed interactions or iceberg keel scouring. The facility consists of a sand channel 4.8m long, 0.8m wide and 0.3 m deep and a trolley, able to move at a controlled velocity ranging from 0.01m/s to 0.2m/s. The trolley is moved along two rails placed on the top of the sand channel by a pulley and wire system driven by an electric motor.
The instrumentation on the trolley consists of an LVDT to measure vertical displacements; a custom-built three-axis load cell to measure the drag, vertical and lateral forces; and a DWT (Draw Wire Transducer) to measure the displacement and the velocity of the trolley. Elements are attached to the load cell and towed along especially prepared sand beds at the desired conditions. The sand beds can be instrumented with pore pressure transducers to monitor the pressure variations associated with the movement of the towed elements. The analogue signals from the load cell, LVDT, DWT and pressure transducers are sampled at 10Hz by a data acquisition system supported by LabVIEW 8.6 software.
In addition, laser elevation and PIV measurements can be undertaken to evaluate the soil deformations induced by the movement of the towed elements at large and small scale, respectively. PIV measurements provide a tool to evaluate the particle displacement field within the soil. To enable this type of measurement, the channel can be transformed into a “half space” by means of a transparent Plexiglas wall. Half models are towed along this transparent wall and soil particles displacements are monitored by high resolution image recoding.