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Article on surfactant impact for superhydrophobic surfaces published in PNAS
Julien and collaborators from UCSB, Princeton and Rennes have just published a study in PNAS showing how the effect of surfactants on superhydrophobic surfaces for microfluidic applications can be estimated using a single non-dimensional number based on a simple ratio including surfactant properties and the length of the air-water interface. This study can help design more effective superhydrophobic surfaces to reduce drag in microfluidic devices. Ref: Temprano-Coleto F., Smith, S. M., Peaudecerf F. J., Landel, J. R., Gibou, F., Luzzatto-Fegiz P. "A single parameter can predict surfactant impairment of superhydrophobic drag reduction". Proc. Nat. Acad. Sci. USA 120(3), e2211092120 |
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Launch of the Roadmap on Quantitative Modelling of Cleaning and Decontamination
With the co-Organizers of the Modelling of Cleaning and Decontamination (ModCaD) Workshop, Julien is sharing the outcomes of this EPSRC-funded workshop in this Roadmap, which reflects the contributions from all the workshop participants. The Roadmap shows the importance of cleaning and decontamination activities across a range of socio-economic sectors and in daily life. It captures the expertise and state-of-the art in terms of the fundamental understanding of the underpinning science behind cleaning and decontamination activities, as well as its practical implementation. The Roadmap also highlights shortcomings and critical needs in the field at the scientific and practical levels, with some strategies to address them. Ref: Wilson D. I., Christie G., Fryer P. J., Hall I. M., Landel J. R., Whitehead K. A. "Lessons to learn from roadmapping in cleaning and decontamination". Food and Bioproducts Processing 135, 156-164 |
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Paper on surfactant spreading in cavities accepted in Journal of Fluid Mechanics
This theoretical paper shows that surfactant spreading near a wall exhibit a singular behaviour at the contact line between the free surface and the wall. The singular behaviour shows an oscillatory behaviour in the interfacial shear, a diverging pressure and a multi-valued vorticity near the contact line. Diffusion can regularize the problem, but over a very small boundary layer which can be hard to capture in numerical simulations. Ref: Mcnair R., Jensen O. E., Landel J. R. (2022) "Surfactant spreading in a two-dimensional cavity and emergent contact-line singularities". Journal of Fluid Mechanics, 930, A15. (Author accepted manuscript) |
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Keynote talk at workshop on the modelling of cleaning and decontamination problems
Julien gave an invited keynote talk on the "fluid mechanics of cleaning and decontamination", as part of the ModCaD EPSRC-funded workshop (slides), where 80 participants from academia, industry and government joined. |
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EPSRC-NSF funded project on the impact of surfactant on turbulent drag reduction for superhydrophobic surfaces
In this project, a joint team of UK and US researchers at the University of Manchester and at the University of California, Santa Barbara, will investigate how surfactant (molecules found for soap, detergent and other natural or man-made substances) impact the drag reduction potential of superhydrophobic surfaces in realistic turbulent flow conditions. This work has applications for maritime transport, pipe flows, submarines, etc. where superhydrophobic surfaces could significantly reduce the energy consumption and associated greenhouse gas emissions. The objective is to identify ways of mitigating the negative effect of surfactant, which are unavoidable in natural environmental conditions. Read our previous work: - Landel, J. R., Peaudecerf, F. J., Temprano-Coleto, F. , Gibou, F., Goldstein, R. E., Luzzatto-Fegiz, P. (2019) "A theory for the slip and drag of superhydrophobic surfaces with surfactant". J. Fluid Mech. 883, A18. (ArXiv) - Peaudecerf, F. J., Landel, J. R., Goldstein, R. E., Luzzatto-Fegiz, P. "Traces of surfactants can severely limit the drag reduction of superhydrophobic surfaces". (2017) PNAS 114, 7254-7259. (Author accepted manuscript) |
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Invited review paper on the fluid mechanics of cleaning and decontamination of surfaces available for preview in Annual Review of Fluid Mechanics
This review paper describes the fundamental underpinning role of fluid mechanics, at the interface with chemistry, surface science and engineering, for the cleaning and decontamination of surfaces. Ref: Landel, J. R., Wilson, D. I. "The fluid mechanics of cleaning and decontamination of surfaces". (2021) Annual Review of Fluid Mechanics 53, 147-171 |
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Paper analyzing the effect of confinement on heat and mass transfer published in the International Journal of Heat and Mass Transfer
This paper studies the impact on convective mass transfer of geometrical confinement effects. Applications are for the cleaning and decontamination of gaps and cracks. Ref: Etzold, M. A., Landel, J. R., Dalziel, S. B. "Three-dimensional advective–diffusive boundary layers in open channels with parallel and inclined walls". (2020) International Journal of Heat and Mass Transfer 153, 119504. (Author accepted manuscript) |
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Paper modelling the impact of surfactant on the drag reduction of superhydrophobic surfaces published in the Journal of Fluid Mechanics
This paper presents a simple scaling model for the complex effect of surfactant on the drag reduction potential of superhydrophobic surfaces in laminar flows. Ref: Landel, et al. "A theory for the slip and drag of superhydrophobic surfaces with surfactant". (2019) Journal of Fluid Mechanics. doi. (ArXiv) |
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Talk at the UK Fluids Conference, University of Cambridge
Julien gives a talk on the "Confinements effects on 3D advection-diffusion boundary layers in U-shape and V-shape channel flows" (slides). |
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SIG Meeting on the Fluid Mechanics of Cleaning and Decontamination
Julien organised the Summer Meeting 2019 of the SIG on the Fluid Mechanics of Cleaning and Decontamination at the Mathematical Institute, University of Oxford, with colleagues from Oxford and Cambridge. It was attended by more than 40 academics and students across UK, EU and US universities, and representatives from Beko, Dstl, Dyson, Sellafield, Smart Separations and Perlemax. Read more... |
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Paper on surfactant solving a maze published in Physical Review Fluids
This paper shows how soap molecules or surfactant at the surface of a milk-filled maze can find their way without any external intervention. They key to finding the exit route is related to endogenous surfactant already present in the milk. See our award winning video on youtube! Ref: Temprano-Coleto, et al. "Soap opera in the maze: Geometry matters in Marangoni flows". Physical Review Fluids 3, 100507. doi (pdf) |
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Talk at the UK Fluids Conference, University of Manchester
Julien gives a talk on "Low order model for the drag reduction of surfactant contaminated superhydrophobic surfaces" (slides). |
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Conference on the Fluid Mechanics of Cleaning and Decontamination
Julien organised a conference on the Fluid Mechanics of Cleaning and Decontamination with SIG co-leader Ian Wilson at the Isaac Newton Institute, Cambridge. It was attended by more than 45 academics and students across UK and EU universities as well as representatives from Dstl, GSK, and Sellafield Ltd. The conference also featured three plenary lectures from Paul Linden (University of Cambridge), Timothy Leighton (University of Southampton) and Stuart Clarke (University of Cambridge). |
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Interview about oil plumes by Tom Rocks Maths and FYFD
Tom Crawford and Nicole Sharpe have interviewed Daria Frank and Julien about their research work on oil plumes and how it can help during future oil spills such as the Deepwater Horizon spill. More details can be found in our recent paper. Full interview: here. |
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Registration now open for the UKFN SIG conference on the Fluid Mechanics of Cleaning and Decontamination
The UK Fluids Network SIG 10 on the Fluid Mechanics of Cleaning and Decontamination organises a conference at the Isaac Newton Institute, Cambridge, on 29-30 August 2018 (see flyer). Registration is here. |
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Guest talk at the Pharmaceutical Manufacturing Technology Centre Workshop, Ireland
Julien gave a guest speech on "Chemical decontamination of impermeable and permeable surfaces" at this one-day workshop on "Process Intelligence - From Data to Action", organised by the Pharmaceutical Manufacturing Technology Centre (PMTC) in Cork, Ireland. |
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Invited talk at the Department of Chemical Engineering and Biotechnology, University of Cambridge
Julien gave a talk on the "Convective mass transfer from a droplet into a submerging falling film". |
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Invited seminar at the IMPRES Colloquium Series of Porous Media
Julien gave a talk on the "Impact of surfactants on the drag reduction of superhydrophobic surfaces" at the School of Chemical Engineering and Analytical Science, University of Manchester. |
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Invited talk at the Edgewood Chemical Biological Center, USA
Julien gave a talk on the "Impact of convective processes on the decontamination of chemical agents" at the Edgewood Chemical Biological Center near Baltimore, MD. |
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Research visit at UC Santa Barbara
Julien is currently visiting collaborators in Mechanical Engineering at the University of California Santa Barbara, where he also gave a talk on "Cleaning and decontamination of droplets on surfaces". |
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Award Winner for our APS Gallery of Fluid Motion video!
Our video "Soap opera in the maze: geometry matters in Marangoni flows" has received an Award Winner at the Gallery of Fluid Motion of the 70th APS DFD meeting in Denver, Colorado US. It is also featured in a post on FYFD. See youtube video here, and our recent paper for relevant explanations on surfactants and Marangoni flows. |
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Video and talks at the APS DFD Meeting
Can soap solve a maze? Check out our Gallery of Fluid Motion video here. Julien and his collaborators are also presenting their latest research progress on superhydrophobic surfaces, cleaning and decontamination processes and oil plumes in the ocean. |
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Talk at the UK Fluids Conference, University of Leeds
Julien gives a talk on the "Role of surfactant in increasing drag over superhydrophobic surfaces". |
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Paper on rotating plumes published in Geophysical Research Letters
This paper shows how the Earth rotation can impact large scale plumes such as the ash clouds from volcanic eruptions or the oil plume from deep water oil leaks. After one rotation period the plume exhibits a precession near the source. Ref: Frank, D., Landel, J. R., Dalziel, S. B., Linden, P. F. "Anticyclonic precession of a plume in a rotating environment". Geophysical Research Letters 44, 9400-9407. doi |
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2017 Summer Meeting of SIG on Fluid Mechanics of Cleaning and Decontamination
Many topics on cleaning and decontamination were discussed at this 2-day meeting held at the School of Mathematics, University of Manchester. It was attended by more than 35 academic members across UK universities as well as representatives of 5 companies: Dstl, Dyson, GDS (Defra), GSK, Sellafield Ltd. Read more |
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