Complex Flow Lab

  • Pattern formation in out-of-equilibrium systems
  • Frictional fluid dynamics, gas/liquid/grain interactions
  • Granular materials, granular flow, segregation
  • Multiphase flows, hydrodynamic flow instabilities
  • Flow in porous media, transforming porous media
  • Fracturing of porous materials, fluid-driven fracturing
  • Complex fluids, granular suspensions, foams, gels, pastes


Dr. Bjørnar Sandnes


Assøciate Prøfessor

College of Engineering, Swansea University (staff profile)

Email: b.sandnes[at]

Tel.: +44 1792 602634 

Dr. Miles Morgan

Miles photo1crop

Postdoctoral Research Associate

Granular flow, complex fluids, pattern formation, rheology

 Dr. James M. Campbell


Postdoctoral Research Associate

Joint project with Porelab, University of Oslo

(Prof. Knut Jorgen Maloy, Prof. Eirik Flekkoy)

Flow instabilities, granular materials, erosion-deposition pattern formation

Dawang Zhang

dawang's photo150-190

PhD student (CSC fellowship)

Multiphase flow, granular materials, pattern formation, hydrophobic granular materials

Second supervisor (Swansea): Prof. Chenfeng Li

Peter Angerman

PhD student

Complex flow patterns in shear thickening suspensions. Experiments and SPH simulations.

Co-supervisor: Prof. Marco Ellero, Basque Center for Applied Mathematics, Spain

Second supervisor (Swansea): Dr. Dan Curtis

Deren Ozturk

PhD student: Graduated 2020

Thesis: Pattern formation and flow to fracture transitions in granular and shear thickening materials

Second supervisor (Swansea): Dr. Anthony Higgins

Gabriel Pronek

MEng research project. Discontinuous shear thickening fluids.


Past members (postdocs, phds, research interns)

Dr. David James (now postdoc at College of medicine, Swansea University)

Dr. Martin Monloubou (now Assistant Professor at ENSTA Bretagne)

Dr. James Matthew Campbell (now postdoc at University of Oslo)

Dr. Benjy Marks (now Lecturer at School of Civil Engineering, University of Sydney)

Rumbidzai Nhunduru (now PhD student at Heriot-Watt University)

Vijesh Karadia

Past Masters project students

Matthew Ashraf (MSc Chemical Engineering), Scott Montgomery (MEng Chemical Engineering), Abodunrin Akinfenwa (MEng Chemical Engineering), Daniel Adam Victor (MSc Chemical Engineering), Salman Ibrahim (MEng Chemical Engineering), Rumbidzai Nhunduru (MSc Chemical Engineering), Michael Banwell-Clode (MEng Chemical Engineering), Khaled Alfangary (MSc Chemical Engineering), Linda Cammue (MSc Chemical Engineering), Emily Sharp (MEng Chemical Engineering), Bishwas Gurung (MSc Chemical Engineering), Ibtisam Al-Abri (MSc Chemical Engineering), Juan Torreblanca (Visiting student)

Past summer project students

Damien Etchecopar, Clovis Sauzaret, Roland Malleville, Ana Clara Gomes, André Machado, Felipe Oliveira Lima, Mariana de Moura, Samanta Bortoni, Clarice de Medeiros, Gabriela Costa, Leonardo Esteves Vaz, Pedro Godinho, Thaís de Sateles, Yuri da Silva, Iuri Michel


The Complex Flow lab is led by Bjornar Sandnes, Associate Professor at College of Engineering, Swansea University. The lab is part of the Impact project housed in the new Engineering North building on the Bay Campus.


We are members of the Centre for Complex Fluids Processing and the Systems and Process Engineering Centre at the College of Engineering, Swansea University.

Bjornar Sandnes is an Associate Member of the new Centre of Excellence “Porelab – Porous Media Laboratory” at NTNU/University of Oslo.


Swansea University Bay Campus


Morgan M.L., James D.J., Monloubou M., Olsen K.S. and Sandnes B. Subdiffusion model for granular discharge in a submerged silo. Phys. Rev. E 104, 044908 (2021).

Morgan M.L. and Sandnes B. From Darcy to Gaussian to fully mobilised grain flow in a confined channel. EPJ Web Conf., 249, 03041 (2021).

Morgan M.L., James D.J., Barron A.R. and Sandnes B. Self-similar velocity profiles and mass transport of grains carried by fluid through a confined channel. Physics of Fluids 32, 113309 (2020).

Ozturk D., Morgan M.L. and Sandnes B. Flow-to-fracture transition and pattern formation in a discontinuous shear thickening fluid. Commun. Phys. 3, 119 (2020).

Dumazer G., Sandnes B., Måløy K.J., and Flekkøy E.G. Capillary bulldozing of sedimented granular material confined in a millifluidic tube. Phys. Rev. Fluids 5, 034309 (2020).

Olsen K.S., Flekkøy E.G., Angheluta L., Campbell J.M., Måløy K.J. and Sandnes B. Geometric universality and anomalous diffusion in frictional fingers. New J. Phys. 21, 063020 (2019).

Ozturk D. and Sandnes B. A study of three-phase fracturing in granular media using high-speed imaging. J. Porous Media 22, 987-1000 (2019). Ozturk 2019 High-speed

Eriksen J.A., Toussaint R., Måløy K.J., Flekkøy E.G., Galland O. and Sandnes B. Pattern formation of frictional fingers in a gravitational potential. Phys. Rev. Fluids 3, 013801 (2018). Eriksen_PRFluids2018_preprint

Correas C., Wright K., Andreoli E., Almutairi Z., Sandnes B. and Barron A.R. Hydration induced morphological change on proppant surfaces employing a calcium-silicate cement system. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 527, 197-209 (2018).

Campbell J.M., Ozturk D. and Sandnes B. Gas-driven fracturing of saturated granular mediaPhys. Rev. Appl. 8, 064029 (2017). Campbell_2017_PRAppl_preprint

Marks B., Eriksen J.A., Dumazer G., Sandnes B., and Måløy K.J.  Size segregation of intruders in perpetual granular avalanches. Journal of Fluid Mechanics, 825, 502-514 (2017). (Marks-JFM2017preprint)

Dumazer G., Sandnes B., Ayaz M., Måløy K.J. and Flekkøy E.G. Self-Structuring of Granular material under Capillary Bulldozing. EPJ Web Conf. 140, (2017).

Toussaint R., Sandnes B., Koehn D., Szymczak P. and Aharonov E. (Editors)  EBook: Flow and Transformations in Porous Media, Frontiers Media SA. (2017).

Sandnes B., Koehn D., Toussaint R., Szymczak P. and Aharonov E.  Editorial: Flow and Transformation in Porous Media. Front. Phys. 4:42. doi: 10.3389/fphy.2016.00042 (2016).

Dumazer G., Sandnes B., Ayaz M., Måløy K.J. and Flekkøy E.G. Frictional fluid dynamics and plug formation in multiphase millifluidic flow. Phys. Rev. Lett. 117, 028002 (2016).(Dumazer_PRL028002, Synopsis: Forming Granular Plugs)

Eriksen J.A., Toussaint R., Måløy K.J., Flekkøy E.G. and Sandnes B. Numerical approach to frictional fingers. Phys. Rev. E. 92, 032203 (2015).

Eriksen J.A., Marks B., Sandnes B. and Toussaint R. Bubbles breaking the wall: Two-dimensional stress and stability analysis. Phys. Rev. E. 91, 052204 (2015).

Marks B., Sandnes B., Dumazer G., Eriksen J.A. and Måløy K.J. Compaction of granular material inside confined geometries. Frontiers in Physics 3, 41 (2015).

Oppenheimer J., Rust A.C., Cashman K.V. and  Sandnes B. Gas migration regimes and outgassing in particle-rich suspensions. Frontiers in Physics 3, 60 (2015).

Sandnes B., Flekkøy E.G., Måløy K.J. Stick slip displacement of confined granular mixtures: bubble expansion. Eur. Phys. J. – ST 204, 19 -25 (2012). (pdf: bubbleexpansion)

Kelf T. A., Gosnell M., Sandnes B., Guller A. E., Shekhter A. B.  and Zvyagin A. V. Scar Tissue Classification Using Nonlinear Optical Microscopy and Discriminant Analysis. J. Biophotonics 5 (2), 159 – 167 (2012). (Kelf_2012)

Sandnes B., Flekkøy E.G., Måløy K.J., Eriksen J.A. The shifting shapes of frictional fluids. Rev. Cub. Fis. 29, 1E23 (2012).

Sandnes B., Kelf T.A., Liu H. and Zvyagin A.V. Retroemission by a glass bead monolayer for high-sensitivity, long-range imaging of upconverting phosphors. Optics Letters 36 (15), 3009 – 3011 (2011).

Sandnes B., Flekkøy E.G., Knudsen H.A., Måløy K.J. and See H. Patterns and flow in frictional fluids. Nature Commun. 2:288 doi:10.1038/ncomms1289 (2011).

Sandnes B. Pattern Palette for complex fluid flows. Physics Today 76, June (2011).

Ignatieva N.Y., Zakharkina O.L., Guller A E., Sandnes B., Shekhter A. B., Kamensky V.A., Zvyagin A. V. Laser-induced modification of the patellar ligament tissue: comparative study of structural and optical changes. Las. Med. Sci. 26 (3), 401 – 413 (2011).

Smith B.R., Inglis D.W., Sandnes B., Rabeau J.R., Zvyagin A.V., Gruber D., Noble C.J., Vogel R., Ōsawa E., Plakhotnik T. Five-nanometer diamond with luminescent nitrogen-vacancy defect centers. Small, 5 (14), 1649 – 1653 (2009).

Sandnes B., Knudsen H. A., Flekkøy E. G. and Måløy K.J. Pattern Transitions in a Granular Fluid System, in Powders and Grains 2009, Proceedings of the 6 International Conference on Micromechanics of Granular Media, Golden, Colorado, USA. 1051-1054, Springer (2009).

Knudsen H. A., Sandnes B., Flekkøy E. G. and Måløy K. J. Labyrinth Patterns in Confined and Tilted Granular-Fluid Systems, in Powders and Grains 2009, Proceedings of the 6 International Conference on Micromechanics of Granular Media, Golden, Colorado, USA.1043-1046, Springer (2009).

Sandnes B., Knudsen H. A., Måløy K. J. and Flekkøy E. G. Pattern formation in slowly drained granular-fluid systems, in Traffic And Granular Flow ’07, Paris, France, edited by Cecile Appert-rolland, Springer (2009).

Sandnes B. and Molenaar D. Emerging stripe patterns in drying suspension droplets, in Traffic And Granular Flow ’07, Paris, France, edited by Cecile Appert-rolland, Springer (2009).

Knudsen H. A., Sandnes B., Flekkøy E. G., and Måløy K. J. Modelling and simulation of a maze-forming process in granular-fluid systems, in Traffic And Granular Flow ’07, Paris, edited by Cecile Appert-rolland, Springer, (2009).

Sandnes B. The physics and the chemistry of the heat pad. Am. J. Phys. 76 (6), 546-550 (2008). (Sandnes2008heatpad)

Knudsen H.A, Sandnes B., Måløy K.J. and Flekkøy E.G. Granular labyrinth structures in confined geometries. Phys. Rev. E 77, 021301 (2008). (Knudsen_pre021301)

Sandnes B., Knudsen H.A., Måløy K.J. and Flekkøy E.G. Labyrinth patterns in confined granular-fluid systems.  Phys. Rev. Lett., 99, 3, 038001 (2007). (Sandnes_prl038001)

Meheust Y., Sandnes B., Løvoll G., Måløy K.J., Fossum J.O., da Silva G. J., Mundim M. S. P.,  Droppa Jr. R and Miranda Fonseca D. Using synchrotron X-ray scattering to study the diffusion of water in a weakly-hydrated clay sample. Clay Science, 12, 66, (2006).

Sandnes B. and Rekstad J.. Supercooling salt hydrates: stored enthalpy as a function of temperature. Solar Energy, 80, 616-625 (2006).

Løvoll G., Sandnes B.,  Måløy K. J., Fossum J. O., Fonseca D. M., Meheust Y., da Silva G. J., Mundim M. S. P.and Droppa Jr. R.  Dynamics of water intercalation fronts in a nano-layered synthetic silicate: A synchrotron X-ray scattering study. Physica B: Condensed Matter, 370, 90-98 (2005).

Schakenda J., Rekstad J., Brnic K., Sandnes B. Stand-alone solar heating system controlled and operated by solar cells, in Proceedings of the 10th International Conference on Solar Energy in High Latitudes-NorthSun, (2005).

Sandnes B. Exergy Efficient Production, Storage and Distribution of Solar Energy. Ph.D thesis. UniPub AS, Oslo, ISSN 1501-7710 No 323, (2004).

Sandnes B. and Rekstad J.. A photovoltaic/thermal (PV/T) collector with a polymer absorber plate. Experimental study and analytical model. Solar Energy 72 (1), 63-73 (2002).

Meir M., Rekstad J., Peter M., Henden L. and  Sandnes B.. Determination of the performance of solar systems with the calorimetric method. Solar Energy 73 (3), 195-207 (2002).

Meir M., Rekstad J. and Sandnes B. Roof Integration of Large Collector Areas – Experiences from Norway, in Proceedings of the Industry Workshop at the Experts meeting of the SHC IEA-Task 26 Solar Combisystems, Experts meeting, Delft, The Netherlands (2001).

Meir M., Rekstad J., Sandnes B.. Solar Combisystems for a multi-apartment building – The Klosterenga residence in Oslo, in Proceedings of the Industry Workshop at the Experts meeting of the IEA-SHC task 26-Solar Combisystems, Helsinki. October 9 (2000).

Sandnes B., Mullane R., Rekstad J.B. and Meir M.G. Phase change materials for storage of solar heat, in 3rd ISES-Europe Solar Congress, Copenhagen, Denmark, June 19-22 (2000).

Sandnes B. and Rekstad J. A photovoltaic/thermal (PV/T) collector with a polymer absorber plate; Experimental study and analytical model, in 3rd ISES-Europe Solar Congress, Copenhagen, Denmark, June 19-22 (2000).

Sandnes J., Forbes T., Hansen R. and Sandnes B.. Influence of particle type and faunal activity on mixing of di(2-ethylhexyl)phthalate (DEHP) in natural sediments. Marine Ecology Progress Series 197, 151 – 167 (2000).

Sandnes J., Forbes T., Hansen R., Sandnes B. and Rygg B.. Bioturbation and irrigation in natural sediments, described by animal-community parameters. Marine Ecology Progress Series 197, 169 – 179 (2000).