Mean Flow and Turbulence Structure of Sediment-Laden Gravity Currents: New Insights using Ultrasonic Doppler Velocity Profiling

  1. William McCaffrey,
  2. Ben Kneller and
  3. Jeff Peakall
  1. J. L. Best2,
  2. A. D. Kirkbride1 and
  3. J. Peakall2

Published Online: 17 MAR 2009

DOI: 10.1002/9781444304275.ch12

Particulate Gravity Currents

Particulate Gravity Currents

How to Cite

Best, J. L., Kirkbride, A. D. and Peakall, J. (2001) Mean Flow and Turbulence Structure of Sediment-Laden Gravity Currents: New Insights using Ultrasonic Doppler Velocity Profiling, in Particulate Gravity Currents (eds W. McCaffrey, B. Kneller and J. Peakall), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304275.ch12

Editor Information

  1. School of Earth Sciences, University of Leeds, Leeds, LS2 9JT, West Yorkshire, UK

Author Information

  1. 1

    Institute of Environmental and Natural Sciences, Lancaster University, Lancaster LA1 4YB, UK

  2. 2

    School of Earth Sciences, University of Leeds, Leeds, LS2 9JT, West Yorkshire, UK

Publication History

  1. Published Online: 17 MAR 2009
  2. Published Print: 24 APR 2001

ISBN Information

Print ISBN: 9780632059218

Online ISBN: 9781444304275

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Keywords:

  • mean flow and turbulence structure of sediment-laden gravity currents - new insights using ultrasonic Doppler velocity profiling;
  • principles of ultrasonic Doppler velocity profiling (UDVP);
  • sediment-laden gravity currents;
  • experimental setup and procedure;
  • schematic experimental setup and grain-size distribution of silica flour;
  • mean flow structure;
  • spatio-temporal series;
  • turbulence structure;
  • flow field visualization

Summary

The mean and turbulent structure of a sediment-laden gravity current is quantified using ultrasonic Doppler velocity profiling (UDVP). UDVP allows both measurements of velocities in opaque fluids and holistic reconstruction of the one-dimensional flow field. This chapter presents results from the first use of UDVP in a sediment-laden gravity current that illustrate: (i) the velocity maximum in the forward flow lies at approximately 0.3 of the head height above the bed; (ii) the region of the velocity maximum of the forward flow is associated with the lowest turbulence intensities within the current; (iii) the highest turbulence intensities are associated with both near-bed shear and mixing on the back of the head; (iv) return flows created by reflection from topography, in the form of different types of bore, may be fully quantified by UDVP; (v) the scale of turbulence associated with the head appears to be of the same order as the head height, and (vi) past studies of gravity currents that have had to use saline solutions and sediment-free dispersions as a proxy for sediment-laden currents, are in many aspects a good substitute for low-density, sediment-bearing gravity currents. Future use of UDVP holds great promise for study of the interaction between turbulence, sediment transport and deposition in a range of sediment-laden flows, including flows where conventional measurement techniques are difficult or impossible to apply.