Turbulence Structure in Steady, Solute-Driven Gravity Currents

  1. William McCaffrey,
  2. Ben Kneller and
  3. Jeff Peakall
  1. C. Buckee,
  2. B. Kneller and
  3. J. Peakall

Published Online: 17 MAR 2009

DOI: 10.1002/9781444304275.ch13

Particulate Gravity Currents

Particulate Gravity Currents

How to Cite

Buckee, C., Kneller, B. and Peakall, J. (2001) Turbulence Structure in Steady, Solute-Driven Gravity Currents, in Particulate Gravity Currents (eds W. McCaffrey, B. Kneller and J. Peakall), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304275.ch13

Editor Information

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

Author Information

  1. 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:

  • turbulence structure in steady, solute-driven gravity currents;
  • ultrasonic Doppler velocity profiling (UDVP);
  • sedimentological fluid dynamics laboratory of University of Leeds;
  • schematic diagram of flume tank where experiments were carried out;
  • Refractive index matching;
  • laser Doppler anemometry;
  • conductivity of aqueous solution of electrolyte;
  • instantaneous velocity and conductivity time series filtered using a technique;
  • turbulence production

Summary

High-resolution turbulence data from refractive index-matched gravity currents have been used to quantify the mean flow and turbulence structure in steady, experimental gravity currents. Comparison of this data-set with experimental and theoretical gravity current data from the literature and with turbulent wall jets, reveals several new insights into both subcritical and supercritical flows. Existing data collapse approaches can be improved with the use of a new characteristic lengthscale taken from the wall jet literature. Turbulence production from shear has been quantified and is seen to be most significant in subcritical currents. Density stratification is also shown to be an important control on the distribution of turbulent kinetic energy. A slow diffusion zone (SDZ) characterized by low turbulence intensities and reduced vertical mass transport in the lower part of the current, around the level of the velocity maximum, has been identified, and related to both density stratification and reduced turbulence production around the velocity maximum. The results presented in this chapter should lead to improved understanding of gravity current dynamics and provide a good test for the output of numerical models.