In conjunction with the 2021 American Geophysical Union Fall Meeting in New Orleans, the UNO Dynamics of Sedimentation Lab will run a live community experiment. The experiment will be conducted in the 22m main channel at UNO and will investigate the controls on bedform three-dimensionality, and the transfer of three-dimensional bedform kinematics into the stratigraphic record. The experiment will coincide with Session EP044: Understanding bedforms across a range of scales and environments.
22m long, 0.6m wide, 0.9m deep recirculating flume, unidirectional current (see https://www.bedform.org/lab for more info).
Flow depth: open for discussion.
Discharge: open for discussion. Can be run with multiple stages to simulate variable hydrograph.
Single Nortek Vectrino Profiling ADV placed at upstream end of profiling reach.
Laser topographic scanner capable of scanning full width of flume for repeat surveys.
- Repeat interval ~30s.
- Scan reach length 2m (up to 10m possible).
- Resolution, up to 250 microns
Laser particle tracking velocimetry (green) for sediment particle tracking in vertically oriented plane.
Black light particle tracking for bed material sediment particle tracking of fluorescent painted particles.
Run time: enough to reach equilibrium at each discharge, while allowing a full set of dunes to fully migrate through the profiling window at each equilibrium condition.
Data and metadata will be published through ScholarWorksUNO upon completion of the experiment run and assigned a DOI, and experiment metadata will be posted onto the Sediment Experimentalist Network wiki (at www.sedexp.net). We are soliciting community input into the experimental setup, additional instrumentation that may be of use, and insights into the open sharing of experimental datasets.
Quick update: we completed the 45Hz runs at high resolution, and are repeating that experiment with longer data collection reach of 9m length to explore the evolution of dune groups (clusters of higher topography/larger dunes spaced by smaller, lower topography dunes) and the stratigraphy they leave behind. Tomorrow we will also start to explore the effect of varying the hydrograph on dune preservation (following on Leary and Ganti, 2020 Geophys. Res. Letters).
The data above shows one 8m long section of the 45Hz, 16cm depth experiment. Z scale in mm (uncorrected for refraction).
So far we have run 3 separate flow conditions to test instrumentation and collect preliminary repeat laser scan data for equilibrium dunes. Scans are being collected approximately 1 per minute, over a 3m reach of the flume. We are shooting for about 12-14 hours of continuous scan data per run.
-35 Hz pump frequency (still need to do discharge calibrations), 13cm depth
-40 Hz pump frequency, 16cm depth
-45 Hz pump frequency, 16cm depth
3D laser scan topography data have been coming out amazing. Below is unprocessed (only gridded to 1mm x 1mm resolution) from the 40 Hz 16cm experiment, scans in the image are separated by 30 minutes. Color scale is in mm however is uncorrected for refraction at the water surface.