Research Theme 7: Deformable porous media

Understand the variety of patterns that form under the combined action of Coulomb friction, capillary- and viscous forces and upgrade the theory and simulations to deal with the whole range of relevant hydrodynamic forces. We will apply this modelling to a real world geological problem of induced seismicity.

Different realisations of a minimalistic simulations of a fluid-grain displacement process governed by friction and capillary forces: The white region represents air, the blue grains. The simulation only takes curvature and self-avoidance into account


We will build algorithmic models that reproduce the many patterns observed in the laboratory, as well as to search for geological consequences of such pattern forming processes. As the deformation rates increase, different forces come into play. First, viscous forces will qualitatively change the displacement patterns by gradually de-mobilizing the Coulomb friction. Then inertial forces will enter the picture along with a stick-slip dynamics. The corresponding numerical models, which take these forces into account, become more challenging as the forces become less local. These models will be built, from the simple to the more complex. We will extend and upgrade existing studies by introducing viscous forces in the invading rather than the defending fluid . We will describe the new patterns by phase-diagram describing the effects of stabilizing, rather than de-stabilizing viscous forces.  As a geological application where the combination of frictional- and fluid pressure forces govern the deformation of a granular material we will model the flow effects leading to induced seismicity from geothermal power plants. This topic is focused on the effects of the combined  injection and extraction of water from  geothermal wells near Strasbourg, the objective being to minimizing risks of induced seismicity. Using geological data from the relevant fault-line and existing seismic records the modelling of the fluid pressure evolution may be used both to explain the onset of previous earthquakes (Strasbourg 2019) and to devise injection/extraction procedures that have a more local and smaller de-stabilizing effect on the fault-zone, thus reducing the risk of triggering seismicity on the regional faults.

Infrared and optical views on a model of ‘Oumuamua as a cometary fractal dust aggregate


Algorithmic models able to predict phase diagrams and provide a quantitative understanding of the dynamics that underlie the patterns of deformable porous media, in particular in the viscously stabilized case. An understanding of optimal operational procedures to avoid induced seismicity from geothermal wells in fault zones.

Principal Investigator:  Professor Eirik Grude Flekkøy.

Recent articles

Papers in pipeline

  • Thorens L., Måløy K. J., Flekkøy E. G. Santucci S.  2022  Capillary washboarding during slow drainage of a frictional fluid, to appear in Phys. Rev. Lett.
  • Zhang D., Campbell J., Eriksen J. A., Flekkøy E. G., Måløy ,K.J., MacMinn C. 2022, Frictional fluid instabilities shaped by viscous forces,  under review Nature Comm