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The relaxation time for viscous and porous gravity currents following a change in flux

Published online by Cambridge University Press:  24 May 2017

Thomasina V. Ball*
Affiliation:
Institute of Theoretical Geophysics, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, CMS Wilberforce Road, Cambridge CB3 0WA, UK BP Institute, University of Cambridge, Cambridge CB3 0EZ, UK Department of Earth Sciences, Bullard Laboratories, University of Cambridge, Madingley Road, Cambridge CB3 0EZ, UK
Herbert E. Huppert
Affiliation:
Institute of Theoretical Geophysics, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, CMS Wilberforce Road, Cambridge CB3 0WA, UK Faculty of Science, University of Bristol, Bristol BS8 1UH, UK School of Mathematics and Statistics, University of New South Wales, Sydney NSW 2052, Australia
John R. Lister
Affiliation:
Institute of Theoretical Geophysics, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, CMS Wilberforce Road, Cambridge CB3 0WA, UK
Jerome A. Neufeld
Affiliation:
Institute of Theoretical Geophysics, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, CMS Wilberforce Road, Cambridge CB3 0WA, UK BP Institute, University of Cambridge, Cambridge CB3 0EZ, UK Department of Earth Sciences, Bullard Laboratories, University of Cambridge, Madingley Road, Cambridge CB3 0EZ, UK
*
Email address for correspondence: tvb21@cam.ac.uk

Abstract

The equilibration time $\unicode[STIX]{x1D70F}$ in response to a change in flux from $Q$ to $\unicode[STIX]{x1D6EC}Q$ after an injection period $T$ applied to either a low-Reynolds-number gravity current or one propagating through a porous medium, in both axisymmetric and one-dimensional geometries, is shown to be of the form $\unicode[STIX]{x1D70F}=Tf(\unicode[STIX]{x1D6EC})$, independent of all the remaining physical parameters. Numerical solutions are used to investigate $f(\unicode[STIX]{x1D6EC})$ for each of these situations and compare very well with experimental results in the case of an axisymmetric current propagating over a rigid horizontal boundary. Analysis of the relaxation towards self-similarity provides an illuminating connection between the excess (deficit) volume from early times and an asymptotically equivalent shift in time origin, and hence a good quantitative estimate of $\unicode[STIX]{x1D70F}$. The case $\unicode[STIX]{x1D6EC}=0$ of equilibration after ceasing injection at time $T$ is a singular limit. Extensions to high-Reynolds-number currents and to the case of a constant-volume release followed by constant-flux injection are discussed briefly.

Type
Papers
Copyright
© 2017 Cambridge University Press 

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References

Bickle, M., Chadwick, A., Huppert, H., Hallworth, M. & Lyle, S. 2007 Modelling carbon dioxide accumulation at Sleipner: implications for underground carbon storage. Earth Planet. Sci. Lett. 255 (1–2), 164176.Google Scholar
Boait, F. C., White, N. J., Bickle, M. J., Chadwick, R. A., Neufeld, J. A. & Huppert, H. E. 2012 Spatial and temporal evolution of injected CO2 at the Sleipner field, North Sea. J. Geophys. Res. 117 (B3), B03309.Google Scholar
Copley, A. & McKenzie, D. 2007 Models of crustal flow in the India-Asia collision zone. Geophys. J. Intl 169 (2), 683698.Google Scholar
Cowton, L. R., Neufeld, J. A., White, N. J., Bickle, M. J., White, J. C. & Chadwick, R. A. 2016 An inverse method for estimating thickness and volume with time of a thin CO2 -filled layer at the Sleipner Field, North Sea. J. Geophys. Res. 121, 50685085.Google Scholar
Griffiths, R. W. 2000 The dynamics of lava flows. Annu. Rev. Fluid Mech. 32, 477518.Google Scholar
Grundy, R. E. & McLaughlin, R. 1982 Eigenvalues of the Barenblatt-Pattle similarity solution in nonlinear diffusion. Proc. R. Soc. Lond. A 383 (1784), 89100.Google Scholar
Hesse, M. A., Tchelepi, H. A., Cantwell, J. & Orr, F. M. Jr. 2007 Gravity currents in horizontal porous layers: transition from early to late self-similarity. J. Fluid Mech. 577, 363383.Google Scholar
Huppert, H. E. 1982 The propagation of two-dimensional and axisymmetric viscous gravity currents over a rigid horizontal surface. J. Fluid Mech. 121, 4358.Google Scholar
Huppert, H. E. 1986 The intrusion of fluid mechanics into geology. J. Fluid Mech. 173 (1), 557594.Google Scholar
Huppert, H. E. & Neufeld, J. A. 2014 The fluid mechanics of carbon dioxide sequestration. Annu. Rev. Fluid Mech. 46, 255272.Google Scholar
Huppert, H .E. & Woods, A. W. 1995 Gravity-driven flows in porous layers. J. Fluid Mech. 292, 5569.Google Scholar
Lyle, S., Huppert, H. E., Hallworth, M., Bickle, M. & Chadwick, A. 2005 Axisymmetric gravity currents in a porous medium. J. Fluid Mech. 543, 293302.Google Scholar
Mathunjwa, J. S. & Hogg, A. J. 2006 Self-similar gravity currents in porous media: linear stability of the Barenblatt-Pattle solution revisited. Eur. J. Mech. (B/Fluids) 25 (3), 360378.Google Scholar
Schoof, C. & Hewitt, I. 2013 Ice-Sheet Dynamics. Annu. Rev. Fluid Mech. 45 (1), 217239.Google Scholar