I am an applied mathematician and fluid dynamicist, and I am interested in using mathematics to model and understand physical processes in the world around us. I am an Associate Professor of Applied Mathematics at University College London. In September 2023 I will be moving to take up an Associate Professorship (of Fluid Dynamics and Sustainability) in the Department of Applied Mathematics and Theoretical Physics (DAMTP) at the University of Cambridge; I will also be a Fellow and Director of Studies in Mathematics at Corpus Christi College, Cambridge.
Research interests
Research areas in which I have worked and topics of current interest include:
- Non-Newtonian fluid mechanics and dynamics of 'structured' fluids: geophysical applications (mud flows, magmatic systems, mud volcanism); industrial applications (mine tailings, batch processing, cleaning)
- Viscoplasticity: channel and displacement flows; viscoplastic boundary layers; locomotion through viscoplastic fluids (swimming in mud and worm locomotion)
- Flows of two-phase suspensionss and granular media
- Clogging and jamming: blood flow and sickle-cell disease; granular patterns in displacement flows
- Poro-elasticity and flow through/of deformable media: applications in geophysics (subsidence, sub-glacial till, liquefaction) and industry (pulp and paper, insulation)
- Thixotropy and liquefaction
- Convection in porous media: impact of heterogeneity; plume dynamics; dissolution and CO2 sequestration; astrophysical convection and internal heat
- Mixing in porous media; viscous fingering
- Glaciological probelems: till mechanics; water transport
- Double-diffusion in geological settings: mid-ocean ridge dynamics, porous media, magma chambers
If you are interested in studying for a PhD or holding a postdoctoral position working with me, or if you are an undergraduate interested in a summer project, please get in touch.
Teaching
(2022/23) I am lecturing the 4th-year course MATH0106: Industrial and Geological Fluids (autumn term) and the 2nd-year course MATH0056: Mathematical Methods 4 (spring term). Please see the relevent Moodle pages for more information.
I am the coordinator for the 4th-year Masters project module (MATH0084); more information can be found here
.Publications
Hinton, E.M., Hewitt, D.R. and Hogg, A.J. Obstructed free-surface viscoplastic flow on an inclined plane, Journal of Fluid Mechanics, 2023 (in press)
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Hogan, K., Warburton, K.L.P., Graham, A.G.C., Neufeld, J.A., Hewitt, D.R., Dowdeswell, J.A. and Larter, R.D. Towards modelling of corrugation ridges at ice-sheet grounding lines, The Cryosphere, 2023 (in press)
Warburton, K.L.P., Hewitt, D.R. and Neufeld, J.A. Shear dilation of subglacial till results in time-dependent sliding laws, Proceedings of the Royal Society A , 2023 479 (20220536)
Hewitt, D.R. Clogged Corners (a Focus on Fluids article), Journal of Fluid Mechanics, 2022 948 (F1) [pdf]
Paterson, D.T., Eaves, T.S., Hewitt, D.R., Balmforth, N.J. and Martinez, D.M. One-dimensional compression of a saturated elastoviscoplastic medium, Physical Review Fluids, 2022 7 (054303) [pdf]
Hewitt, D.R. Evolution of convection in a layered porous medium, Journal of Fluid Mechanics, 2022 941 (A56) [pdf]
Nijjer, J.S., Hewitt, D.R., and Neufeld, J.A.. Horizontal miscible displacements through porous media: the interplay between viscous fingering and gravity segregation, Journal of Fluid Mechanics, 2022 935 (A14) [pdf]
Hewitt, D.R. and Balmforth, N.J. Locomotion with a wavy cylindrical filament in a yield-stress fluid, Journal of Fluid Mechanics, 2022 936 (A17) [pdf]
Doyle S.H., Hubbard B., Christoffersen P., Law R., Hewitt D.R., Neufeld J.A., Schoonman C.M., Chudley T.R., Bougamont M. Water flow through sediments and at the ice-sediment interface beneath Sermeq Kujalleq (Store Glacier), Greenland, Journal of Glaciology, 2021 (1-20) [pdf]
Balmforth, N.J., Craster, R.V. and Hewitt, D.R. Building on Oldroyd's viscoplastic legacy: perspectives and new developments, Journal of Non-Newtonian Fluid Mechanics, 2021 294 (104580) [pdf]
Le Reun, T. and Hewitt, D.R. High-Rayleigh-number convection in porous-fluid layers, Journal of Fluid Mechanics, 2021 920 (A35) [pdf]
Paterson, D.T., Eaves, T.S., Hewitt, D.R., Balmforth, N.J. and Martinez, D.M. On two-phase modeling of dewatering pulp suspensions, AIChE Journal, 2021 67 (e17277) [pdf]
Warburton, K.L.P., Hewitt, D.R. and Neufeld, J.A. Tidal Grounding-Line Migration Modulated by Subglacial Hydrology, Geophysical Research Letters, 2020, 47 (e2020GL089088) [pdf]
Le Reun, T. and Hewitt, D.R. Internally heated porous convection: an idealised model for Enceladus' hydrothermal activity, Journal of Geophysical Research: Planets, 2020, 125 (e2020JE006451) [pdf]
Hewitt, D.R. Vigorous convection in porous media, Proceedings of the Royal Society A (review article) 2020 476 (20200111) [pdf]
Daneshi, M., MacKenzie, J., Balmforth, N.J., Martinez, D.M. and Hewitt, D.R. Obstructed viscoplastic flow in a Hele–Shaw cell, Physical Review Fluids 2020 5 (013301) [pdf]
Warburton, K.L.P., Hewitt, D.R. and Neufeld, J.A. The elastic Landau-Levich problem on a slope, Journal of Fluid Mechanics, 2020 883 (A40) [pdf]
Hewitt, D.R., Peng, G.G., and Lister, J.R. Buoyancy-driven plumes in a layered porous medium, Journal of Fluid Mechanics, 2020 883 (A37) [pdf]
Supekar, R., Hewitt, D.R. and Balmforth, N.J. Translating and squirming cylinders in a viscoplastic fluid, Journal of Fluid Mechanics, 2020 882 (A11) [pdf] (see also Front-cover picture of journal)
Eaves, T.S., Paterson, D.T., Hewitt, D.R., Balmforth, N.J. and Martinez, D.M. Dewatering saturated, networked suspensions with a screw press, Journal of Engineering Mathematics, 2019 doi:10.1007/s10665-019-10029-3 [pdf]
Paterson, D.T., Eaves, T.S., Hewitt, D.R., Balmforth, N.J. and Martinez, D.M. Flow-driven compaction of a fibrous porous medium, Physical Review Fluids, 2019 4 (074306) [pdf]
Nijjer, J.S., Hewitt, D.R., and Neufeld, J.A. Stable and unstable miscible displacements in layered porous media, Journal of Fluid Mechanics, 2019 869 (468-499) [pdf]
Hewitt, D.R., and Balmforth, N.J. Viscoplastic slender-body theory, Journal of Fluid Mechanics, 2018 856 (870-897) [pdf] (see also 'Focus on Fluids' review article Dropping slender-body theory into the mud by Saverio Spagnolie)
Hewitt, D.R., Chini, G.P. and Neufeld, J.A. The influence of a poroelastic till on rapid subglacial flooding and cavity formation, Journal of Fluid Mechanics, 2018 855 (1170-1207) [pdf]
Nijjer, J.S., Hewitt, D.R., and Neufeld, J.A. The dynamics of miscible viscous fingering from onset to shutdown, Journal of Fluid Mechanics, 2018 837 (520-545) [pdf]
Hewitt, D.R., and Lister, J.R., Stability of columnar convection in a three-dimenional porous medium, Journal of Fluid Mechanics, 2017 829 (89-111) [pdf]
Hewitt, D.R., and Balmforth, N.J., Taylor's swimming sheet in a yield stress fluid, Journal of Fluid Mechanics, 2017 828 (33-56) [pdf]
Kvick, M., Martinez, D.M., Hewitt, D.R., and Balmforth, N.J., Imbibition with swelling: Capillary rise in thin deformable porous media, Physical Review Fluids, 2017 2 (074001) [pdf]
Balmforth, N.J., Craster, R.V., Hewitt, D.R., Hormozi, S., and Maleki, A., Viscoplastic boundary layers, Journal of Fluid Mechanics, 2017 813 (929-954) [pdf]
Liu, Y., Balmforth, N.J., Hormozi, S. and Hewitt, D.R., Two-dimensional viscoplastic dambreaks, Journal of Non-Newtonian Fluid Mechanics, 2016 238 (65-79) [pdf]
Hewitt, D.R., Paterson, D.T., Balmforth, N.J., and Martinez, D.M. Dewatering of fibre suspensions by pressure filtration, Physics of Fluids, 2016 28 (063304). [pdf]
Hewitt, D.R., Nijjer, J.S., Neufeld, J.A., and Worster, M.G. Flow-induced compaction of a deformable porous medium, Physical Review E, 2016 93, 023116 [pdf]
Hewitt, D.R., Balmforth, N.J., Dasani, M., and Martinez, D.M. Obstructed and channelized viscoplastic flow in a Hele-Shaw cell, Journal of Fluid Mechanics, 2016 790 (173-204) [pdf]
Hewitt, D.R., Neufeld, J.A., and Balmforth, N.J. Shallow, gravity-driven flow in a poro-elastic layer, Journal of Fluid Mechanics, 2015 778 (335-360) [pdf]
Hewitt, D.R., Neufeld, J.A., and Lister, J.R. High Rayleigh number convection in a porous medium containing a thin low-permeability layer, Journal of Fluid Mechanics, 2014 756 (844-869) [pdf]
Hewitt, D.R., Neufeld, J.A., and Lister, J.R. High Rayleigh number convection in a three-dimensional porous medium, Journal of Fluid Mechanics, 2014 748 (879-895) [pdf]
Hewitt, D.R., Neufeld, J.A., and Lister, J.R. Stability of columnar convection in a porous medium, Journal of Fluid Mechanics, 2013 737 (205-231) [pdf]
Hewitt, D.R., and Balmforth, N.J. Thixotropic gravity currents, Journal of Fluid Mechanics, 2013 727 (56-82) [pdf]
Hewitt, D.R., Neufeld, J.A., and Lister, J.R. Convective shutdown in a porous medium at high Rayleigh number, Journal of Fluid Mechanics, 2013 719 (551-586) [pdf] (see also 'Focus on Fluids' review article by David Pritchard, and Front-cover picture)
Hewitt, D.R., Neufeld, J.A., and Lister, J.R. Ultimate regime of high Rayleigh number convection in a porous medium, Physical Review Letters, 2012 108 (224503) [pdf]
Previously
From 2019-2022 I was a Lecturer at UCL; from 2015-2019 I was a Research Fellow and, latterly, Tutor, at Gonville and Caius College, University of Cambridge. Prior to that, I was a Killam Postdoctoral Research Fellow in the Department of Mathematics at the University of British Columbia, Vancouver (2014-2015).
I hold a Ph.D. in Applied Mathematics from the University of Cambridge; my PhD thesis, entitled 'High Rayleigh number Convection in a Porous Medium', can be found here.
Contacts
email: d.hewitt 'at' ucl.ac.uk
Office: Room 700, 25 Gordon Street
Address:
Department of Mathematics, University College London,
25 Gordon Street, Bloomsbury, London WC1H 0AY
Telephone: 0207679 2842