| 94 | 94 | The siphon rig consists of 12 siphon tubes, each with a nominal internal diameter of 1.6 mm (3.2. mm external diameter), and 15 m in length. The siphons are held in place by a plastic holder which is in turn connected to a rod attached to the channel. The siphon rig is positioned 80 mm downstream of the inflection downstream of bend 2, offset laterally 78 mm off-axis from the position of the UVP (on the right hand side as looking downstream). The siphons are positioned at heights of 10, 25, 50, 75, 100, 125, 150, 175, 200, 250, 350 and 450 mm above the bed. The siphon tubes are connected to a 12 head peristaltic pump. Samples are taken when the traverse (with ADVs and conductivity probe) is positioned upstream measuring the straight section. Samples are collected in an array of 12 plastic containers over a 60 second period, starting at 5, 10, 15, 20, 25, 30 and 35 minutes into the experiment (the start of the experiment is defined as that point where the input is steady). Samples are subsequently measured for conductivity using an Anton Paar DMA35 Portable Density Meter. |
