The Environmental Sedimentary Fluid Dynamics Laboratory is situated on Floor 02 of the School of Environmental Sciences, UEA. It houses a wide range of equipment for examining sediment and for undertaking physical experiments on sediment and water flow. It was refurbished early in 2005. For more information on the facility click on topics in the Research box to the left.
Faculty Involved in the Laboratory
- Jenny Stevenson (support services staff)
- John Brindle (support services staff)
- Emma Knight (support services staff)
- Maria Martinez de Alvaro (PhD student)
- Mel Froude (PhD student)
- Christopher Herbert (MSci student)
Collaborators in Other Organisations
- John Bacon (Cefas)
- Robert Macdonald (Bangor)
This 6 m long, 0.3 m wide, 0.5 m deep tank is designed to allow generation of surge-type or sustained turbidity currents, on to a flat tank floor or more complex topography.
Research Programme for Density Current Tank
- January 2006-2008: Carbonate turbidity currents, James Hodson + Jan Alexander.
- October-December 2005: Turbidity current bypass, Tom White + Jan Alexander.
Publications Resulting from Recent Research in the ENV Density Current Tank
- Hodson, J.M. & Alexander, J. (2010) The effects of grain-density variation on turbidity currents and some implications for the deposition of carbonate turbidies. Journal of Sedimentary Research 80, 515-528. doi: 10.2110/jsr.2010.051.
- Gray, T., Alexander, J. & Leeder, M.R. (2005) Quantifying velocity and turbulence structure in depositing sustained turbidity currents across breaks in slope, Sedimentology, 52, 467-488.
- Leeder M.R., Gray, T.E. & Alexander, J. (2005) On universal criteria for turbulent sediment suspension, Sedimentology, 52, 683-691.
This new flume is designed for recirculating water and sediment under a wide range of conditions, to allow study of physical, chemical and biological interactions between water and sediment.
The tilting flume, has a 10 m straight observation section with a 1 m by 1 m cross section and all parts are corrosion resistant. The system is designed to allow a maximum of 1.5 m/sec at a water depth of 0.3 m and zero bed slope, but varying discharge, bed slope and water depth produces a wide range of conditions. For more information click on current projects and equipment list in menu to left.
Research Programme for Flume
- January 2011 - April 2013: Crossbedding in sand
- June - September 2012: Scour around "tree trunks" at different inclination angles.
- November - December 2012: Counter flow ripples.
- October 2006 - October 2009: Sedimentary behaviour in hydraulic jumps
- May-June 2005: Commissioning experimentation and snagging.
- June-July 2005: Correlating the acoustic response of the rotary scanning sonar to bedform height and wavelength, John Bacon, Robert Macdonald.
- July-August 2005: Assessing the relative value of acoustic profiler and other instrumentation for assessing bedform shape and migrations, Jan Alexander + Akash Rughani.
- August 2005: Testing new current indicators.
- April 2006: Bed load investigations.
- November-December 2005: Equipment installation and development.
Two rooms in the lab suite are dedicated to grain size analysis.
The ability to quantify particle size distributions is essential in various areas of Environmental Sciences and particularly important in understanding sediment movement, material properties and is a cornerstone in characterising soils.
This is the main stay of sand and gravel grade analysis and the means of producing size separates for further study.
- Laser Diffraction Particle Size Analyser
Ultrasonic Bed Profiler (UBP)
An UBP and positioning support frame will allow continuous acquisition of bed profile data through fluid flows of various types. The UBP uses an echo sounding principle to determine the depth to the bed directly below the probe quickly and accurately (to 0.1mm).
Non-intrusive acoustic velocity metres measuring a flow point under the probe. 4-component velocities are achieved (streamwise, cross-stream and 2 vertical components).
Ultrasonic Doppler velocity profiler system (UDVP)
The ultrasonic velocity profiler system has 10 x 4 MHz probes (transducers) capable of measuring and recording velocity profiles in water and water transporting sediment from static equipment positions. Individual probes (transducers) are able to measure velocity profiles in water along a single line and the positioning of the probes should be flexible.
Acoustic Back Scatter System (ABS)
Rotary Scanning Sonar
The calibration tank:
Calibrating the backscatter system for different sand and ballotini samples. The tank recirculates uniformly mixed sediments and allows siphon sampling of the water.
The demonstration flume:
A useful teaching device and used to quick-trial ideas for the large research flume.
The laboratory has various portable devices used for measuring erosion of sediments, including 2x Cohesive Strength Meter (CSM), an EROMES and FloWave.
Counter flow ripples
Counter-flow ripples can form within the lee side eddy of a unit bar or dune. They have been observed preserved in numerous fluvial sedimentary deposits; however the circumstances that lead to their formation are poorly understood. A series of flume experiments is being undertaken to deduce the conditions these bedforms are created under, specifically focusing on the flow separation zone downstream of a unit bar. If these conditions can be deduced preserved counter-flow ripples maybe helpful in the palaeoenvironmental interpretation of fluvial sedimentary deposits in the geological record.
Cross bedding slope
The significance of grain density in controlling turbidity current flow - James Hodson and Jan Alexander
The geometry and character of the deposits of dilute gravity currents (e.g. turbidity currents which transport coarse sediment in to the deep sea) are controlled by sediment fall out rate. Grain settling velocities therefore controls deposit character. Grain size, shape, density, surface texture, sorting and concentration control grain settling velocity. Previous research on turbidity currents has focused on the grain size as the major control on settling velocity and therefore turbidite character. A series of experiments have been undertaken to assess the significance of grain density in controlling turbidity current flow and sedimentation behaviour. Experiments examined the differences in behaviour between of suspensions of dense and less dense particles and in a series of mixtures. The aim was to determine how particle density affects the transport efficiency of sediment in turbidity currents in order to understand how on aspect of carbonate sediment properties may produce turbidites that differ from their more commonly studied siliciclastic counterparts.
Hodson, J. and Alexander, J. (2010) The effects of grain-density variation on tubidity currents and some implications for the deposition of carbonate turbidities. Journal of Sedimentary Research 80, 515-528. doi: 10.2110,jsr.2010.051.
Sedimentation under a subaerial hydraulic jump - Robert G. Macdonald, Jan Alexander, John C. Bacon and Mark J. Cooker (Maths)
A series of flume experiments are being undertaken to determine the interaction of flow and sediment within hydraulic jumps and to determine the sedimentary depositional architecture(s) that may be produced by hydraulic jumps. During the initial runs, sand features formed which prograded upstream and downstream simultaneously and produced a unique depositional architecture. These have since been termed hydraulic-jump unit bars. A series of these unit bars may overlay each other to form a hydraulic-jump bar complex.
- Macdonald, R.G., Alexander, J., Bacon, J.C & M.J. Cooker (2009) Flow patterns, sedimentation and deposit architecture under a hydraulic jump on a non-eroding bed; defining hydraulic-jump unit bars. Sedimentology, 56, 1346-1367. doi: 10.1111/j.1365-3091.2008.01037.x.
Macdonald, R.G., Alexander, J., Bacon, J.C. & Cooker, M.J. submitted. Variations in the architecture of hydraulic-jump bar complexes on non-eroding beds. Sedimentology.
FLOCSAM NERC-funded "Acoustic and optical backscatter from flocculating sediments" - Chris Vincent, Tony Dolphin, Iain MacDonald
FLOCSAM will investigate the long-standing and scientifically-challenging problem of how sound responds to muddy sediments and develop, through a combination of theory and experiment, algorithms capable of quantitatively inverting acoustic backscatter signals from cohesive sediment to predict mass concentration, and to combining these with the best features of optical sensors. The theoretical component will build on the existing experience with backscatter models for sand, informed by tank, flume and field results. Small-scale (Couette-type tank) and medium-scale (flume) lab experiments will be conducted, controlling the flocculation processes, using simple clay suspensions and culminating in a full-scale field campaign in a muddy estuary. The lab and field trials will use ABS, ADV and ADCP, OBS, LISST-100 and imaging-technology, plus pump-sampling, velocity and turbulence measurements. In collaboration with Professor Peter Thorne (Proudman Oceanographic Labs); Dr Sarah Bass and Dr Andrew Manning, University of Plymouth.>