| 89 | | Three profiling Acoustic Doppler probes will be used for mapping three-component flow velocities within the channel. These probes come in two types, 1 is a stem probe with additional shielding, and two are flexible probes that allow closer deployment. All three probes measure three component velocities over a depth range of around 30 mm (up to 34 mm), with this zone starting 40 mm below the probe head. Bottom tracking by the instruments enables this depth to be precisely known and controlled, provided sufficient seeding is present in the flow. These probes are co-mounted on the traverse in order to collectively measure over a height of approximately 6 cm. Movement of these probes on the traverse in the y and z planes allows detailed vertical profiles and flow mapping to be undertaken. Dwell times at each point will vary between 30 and 60 seconds depending on the nature of the experiment. The basal probe is numbered 1, middle 2, and upper probe 3, and are at heights of 7.2, 10 and 13 cm respectively. Lateral offset in the x direction is 8.5 cm between probes 1 and 2, and 7.5 cm between probes 2 and 3. The traverse positions for each cross-section are based on probe 2 being positioned directly above the cross-section. The aim is to synchronise the ADV collection with the traverse through sending of the required voltage offset signal to them, thus enabling individual velocity files to be collected for each probe at each traverse. |
| | 89 | Three profiling Acoustic Doppler probes will be used for mapping three-component flow velocities within the channel. These probes come in two types, 1 is a stem probe with additional shielding, and two are flexible probes that allow closer deployment. All three probes measure three component velocities over a depth range of around 30 mm (up to 34 mm), with this zone starting 40 mm below the probe head. Bottom tracking by the instruments enables this depth to be precisely known and controlled, provided sufficient seeding is present in the flow. These probes are co-mounted on the traverse in order to collectively measure over a height of approximately 6 cm. Movement of these probes on the traverse in the y and z planes allows detailed vertical profiles and flow mapping to be undertaken. Dwell times at each point will vary between 30 and 60 seconds depending on the nature of the experiment. The basal probe is numbered 1, middle 2, and upper probe 3, and are at heights of 7.2, 10 and 13 cm respectively. Lateral offset in the x direction is 8.5 cm between probes 1 (most downstream probe) and 2, and 7.5 cm between probes 2 and 3 (most upstream probe). The traverse positions for each cross-section are based on probe 2 being positioned directly above the cross-section. The aim is to synchronise the ADV collection with the traverse through sending of the required voltage offset signal to them, thus enabling individual velocity files to be collected for each probe at each traverse. |
