Article
Mechanics
Tobias Baier, Steffen Hardt
Summary: This study investigates the impact of insoluble surfactants on shear flow along a superhydrophobic surface in Cassie state. Analytical results for surfactant distribution on a groove and the corresponding flow field in its vicinity are derived for both a single groove and an array of evenly spaced grooves under convection-dominated transport. The relationship between the applied shear stress and the effective slip length on the microstructured surface is examined for an array of grooves.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Johan Sundin, Shervin Bagheri
Summary: This study investigates the effects of surfactants on liquid-infused surfaces and finds that they may have more severe impacts compared to superhydrophobic surfaces. An analytical model is constructed to predict the critical surfactant concentration at which the slip length decreases significantly.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Tobias Baier, Steffen Hardt
Summary: This study investigates shear-driven liquid flow over a planar surface with an embedded gas-filled groove, revealing that recirculating flow occurs when the gas-liquid interface slightly protrudes or embeds into the surface, while no flow is induced on a planar gas-liquid interface. The validity of the expansion is assessed by comparing the obtained analytical results with numerical calculations. This research sheds light on the mobility of curved gas-liquid interfaces in the presence of surfactants acting as an incompressible surface fluid.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Henry Rodriguez-Broadbent, Darren G. Crowdy
Summary: At high surface Peclet numbers, the presence of surfactants can lead to surface immobilization, but a different mechanism is proposed for longitudinal shear flow along a unidirectional trench at high Marangoni numbers, where the meniscus becomes a constant-shear-stress surface due to contamination by surfactant. Experimental observations support the presence of recirculating interfacial flows on the meniscus. By calculating slip lengths, it is shown that the effective immobilization of the surfaces with vortical flows on the meniscus highlights the caution needed when comparing theory and experiments based on effective slip properties alone.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Samuel D. Tomlinson, Frederic Gibou, Paolo Luzzatto-Fegiz, Fernando Temprano-Coleto, Oliver. E. E. Jensen, Julien. R. R. Landel
Summary: This study investigates the effect of soluble surfactant on the performance of superhydrophobic surfaces (SHSs) in drag reduction applications. By analyzing the transport of surfactant in a three-dimensional laminar channel flow, a one-dimensional model is derived to predict drag reduction and surfactant distribution. The importance of this study lies in providing insights into the underlying physics of the drag reduction effect through analysis of velocity field and surfactant concentrations.
JOURNAL OF FLUID MECHANICS
(2023)
Review
Chemistry, Multidisciplinary
Christopher Vega-Sanchez, Chiara Neto
Summary: The correct theoretical definition of boundary conditions for flow is essential for fluid dynamics studies, especially in confined nano- and micro-scale flows. The pressure drop versus flow rate method is useful for detecting microscale interfacial slip and drag reduction. Comparing accurate experiments with theoretical models can provide clarity on slip mechanisms on smooth and structured surfaces.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Engineering, Chemical
Huilong Yan, Wenyao Zhang, Yonghe Cui, Fang Qian, Dongmin Wei, Panpan Guo, Kai Jiao, Jin Huang, Qiuwang Wang, Cunlu Zhao
Summary: This study proposes a method for fabricating lubricant infused surfaces (LIS) on the inner walls of metal capillaries to achieve sustainable drag reduction and anti-corrosion properties. The experimental results show that LIS metal capillaries exhibit durable drag reduction and anti-corrosion characteristics, and the drag reduction performance can be effectively tuned by varying the viscosity of infusion lubricants.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Mechanics
Tongtong Tao, Zhaochang Wang, Jiawei Ji, Yuhang Guo, Yongqing Zhu, Xidong Hu, Kun Liu, Yunlong Jiao
Summary: In this study, a deflecting air cavity generation strategy utilizing superhydrophobic area occupancy and impact angle control is reported. The influence of these factors on water entry dynamics and drag reduction characteristics of spheres is investigated through experimental and theoretical analysis. The results show that the deflection displacement of a hemispherically coated sphere reaches its maximum when the impact angle is 90 degrees. The SHB region-modulated sphere exhibits different air cavity morphologies and achieves faster movement with reduced drag.
Article
Mechanics
J. M. Floryan, N. N. Haq
Summary: The study focused on the effects of surface vibrations on propulsion augmentation and resistance in the relative movement of parallel plates. It was found that wave velocity plays a crucial role in flow resistance, with slower waves tending to increase flow resistance, while supercritical waves generally decrease resistance and can lead to a complete elimination of resistance.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Qian Mao, Jiazhen Zhao, Yingzheng Liu, Hyung Jin Sung
Summary: This study investigates the hydrodynamic mechanism of drag reduction by a flexible hairy coating through simulations and experimental data comparison, revealing the importance of flexible hairy coatings in drag reduction and the effects of different parts of the coating on drag reduction.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Longyin Jiao, J. M. Floryan
Summary: Analysis of pressure losses in laminar, pressure-gradient-driven channel flows with wall transpiration shows that reduction in effective channel opening, nonlinear streaming, and elimination of direct contact between fluid and walls influence these losses. Proper selection of transpiration pattern can reduce pressure losses, with nonlinear streaming being the dominant effect. Increasing transpiration at both walls can further decrease losses when in proper relative position, but concentrating transpiration at a single wave number achieves the largest reduction. The use of transpiration increases energy cost of flow, with optimization of conditions leading to minimization of this cost for most effective propulsion augmentation.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
M. Z. Hossain, J. M. Floryan
Summary: It is found that applying thermal waves on a horizontal slot surface can generate a pumping effect. The change in flow field due to thermal inertia drives the net fluid movement in the horizontal direction. The induced flow rate increases with wave speed but decreases when the convection becomes limited. Excessive wavelength and excessive decrease in wavelength reduce the flow rate. The pumping effect can be optimized by selecting the appropriate wave speed and wavelength of the thermal wave. The magnitude of pumping increases with a reduction of Prandtl number.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Azadeh Jafari, Beverley J. McKeon, Maziar Arjomandi
Summary: The potential of frequency-tuned surfaces as a passive control strategy for reducing drag in wall-bounded turbulent flows is investigated using resolvent analysis. It is shown that wall impedance can suppress the modes resembling the near-wall cycle and the very-large-scale motions and the Reynolds stress contribution of these modes. Furthermore, a wall with only shear-driven impedance is found to suppress turbulent structures over a wider range in spectral space, leading to an overall turbulent drag reduction.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Chemistry, Analytical
Rui You, Hang Wu, Wei Pang, Xuexin Duan
Summary: This paper presents a gigahertz bulk acoustic streaming tweezer (AST)-based micro-manipulation platform that can precisely and arbitrarily manipulate a single particle's movement. By controlling radio frequency signals, the intensity and direction of the acoustic streaming flow can be adjusted, allowing for versatile particle manipulation. The platform shows promising potential in various applications such as separation, assembly, sensing, and transportation.
ANALYTICAL CHEMISTRY
(2022)
Article
Multidisciplinary Sciences
Giulio Foggi Rota, Alessandro Monti, Marco E. Rosti, Maurizio Quadrio
Summary: Viscous dissipation in fluid flows causes significant energy losses. Laminar flows in ducts have minimum resistance, while turbulence increases friction and energy requirements for pumping. A novel technique of intermittently pumping the flow accelerates it to a quasi-laminar state, saving energy compared to constant pumping and reducing harmful emissions.
SCIENTIFIC REPORTS
(2023)
Article
Mechanics
D. Frank, Julien R. Landel, Stuart B. Dalziel, P. F. Linden
Summary: The laboratory results reveal specific changes in the behavior of bubble plumes at different rotation rates, such as the slowing down of plume width growth at certain rotation rates, and the inhibitory effect of surface rotation on the lateral dispersion of bubbles.
JOURNAL OF FLUID MECHANICS
(2021)
Letter
Immunology
Paolo Luzzatto-Fegiz, Fernando Temprano-Coleto, Francois J. Peaudecerf, Julien R. Landel, Yangying Zhu, Julie A. McMurry
JOURNAL OF INFECTIOUS DISEASES
(2021)
Article
Biology
Thomas C. Day, Stephanie S. Hohn, Seyed A. Zamani-Dahaj, David Yanni, Anthony Burnetti, Jennifer Pentz, Aurelia R. Honerkamp-Smith, Hugo Wioland, Hannah R. Sleath, William C. Ratcliff, Raymond E. Goldstein, Peter J. Yunker
Summary: The prevalence of multicellular organisms is due to their ability to form complex structures. This study quantifies the statistics of cellular neighborhoods in two different multicellular eukaryotes and finds that the cell neighborhood sizes closely fit a gamma distribution. This suggests that gamma-distributed cell neighborhood sizes are a general feature of multicellularity, providing predictability in cell packing.
Article
Physics, Multidisciplinary
George T. Fortune, Nuno M. Oliveira, Raymond E. Goldstein
Summary: This study investigates the growth of biofilms in confined spaces. By utilizing a poroelastic framework, the radial growth mechanism of biofilms is revealed, and it is found that the growth of biofilms is limited by the Poisson's ratio of the matrix.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Trang T. H. Nguyen, Emily J. Zakem, Ali Ebrahimi, Julia Schwartzman, Tolga Caglar, Kapil Amarnath, Uria Alcolombri, Francois J. Peaudecerf, Terence Hwa, Roman Stocker, Otto X. Cordero, Naomi M. Levine
Summary: Micro-scale microbial community dynamics significantly impact the fate of sinking particles in the ocean, playing a crucial role in global carbon cycling and future climate. By scaling-up essential features of particle-associated microbial dynamics, this study provides mechanistic insight into the contribution of microbes to the vertical carbon flux in the ocean.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Frederic de Schaetzen, Mingzhen Fan, Uria Alcolombri, Francois J. Peaudecerf, David Drissner, Martin J. Loessner, Roman Stocker, Markus Schuppler
Summary: This study investigates the predation interactions between Acanthamoeba and Listeria monocytogenes and uncovers the mechanism of backpack formation by Acanthamoeba. The results indicate that backpack formation is not driven by bacterial chemotaxis, but rather initiated by random encounters and the movement of amoebae. This finding contributes to a better understanding of the dynamics and ecological roles of microbial communities.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Biotechnology & Applied Microbiology
D. I. Wilson, G. Christie, P. J. Fryer, I. M. Hall, J. R. Landel, K. A. Whitehead
Summary: The UK's Engineering and Physical Sciences Research Council supported a series of meetings in 2021 to develop a roadmap for future research in Quantitative Modelling in Cleaning and Decontamination. This activity involved identifying past and current activities on this topic across different fields and confirmed the common needs and challenges across sectors.
FOOD AND BIOPRODUCTS PROCESSING
(2022)
Article
Thermodynamics
Joel Daou, Aiden Kelly, Julien Landel
Summary: A two-dimensional model for premixed flames accounting for flow-enhanced diffusion or Taylor dispersion and heat loss is investigated. The effects of Taylor dispersion on thermo-diffusive instabilities of non-adiabatic flames are analyzed. Theoretical and numerical studies show that Taylor dispersion and heat loss significantly affect flame stability.
COMBUSTION AND FLAME
(2023)
Article
Mechanics
Samuel D. Tomlinson, Frederic Gibou, Paolo Luzzatto-Fegiz, Fernando Temprano-Coleto, Oliver. E. E. Jensen, Julien. R. R. Landel
Summary: This study investigates the effect of soluble surfactant on the performance of superhydrophobic surfaces (SHSs) in drag reduction applications. By analyzing the transport of surfactant in a three-dimensional laminar channel flow, a one-dimensional model is derived to predict drag reduction and surfactant distribution. The importance of this study lies in providing insights into the underlying physics of the drag reduction effect through analysis of velocity field and surfactant concentrations.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Thermodynamics
Samuel D. Tomlinson, Francois J. Peaudecerf, Fernando Temprano-Coleto, Frederic Gibou, Paolo Luzzatto-Fegiz, Oliver E. Jensen, Julien R. Landel
Summary: Superhydrophobic surfaces (SHSs) have the ability to reduce friction drag in turbulent flows. However, the impact of surfactants on the drag-reducing properties of SHSs under turbulent flow conditions has not been thoroughly studied, as it is currently expensive to predict in direct numerical simulations.
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2023)
Article
Mechanics
Merlin A. Etzold, George T. Fortune, Julien R. Landel, Stuart B. Dalziel
Summary: This study investigates the swelling of a thin hydrogel layer by a single water drop through experimental and theoretical approaches. Fast absorption leading to radial spreading blister is observed, and a one-dimensional nonlinear diffusion equation is used to describe the evolution of the blister geometry.
JOURNAL OF FLUID MECHANICS
(2023)
Review
Biology
Jonasz Slomka, Uria Alcolombri, Francesco Carrara, Riccardo Foffi, Francois J. Peaudecerf, Matti Zbinden, Roman Stocker
Summary: Properties of microbial communities emerge from interactions between microorganisms and between microorganisms and their environment. To quantify and design these interactions, it is necessary to quantify encounter rates, which can often be done through encounter kernels. However, encounter kernels are often overlooked in descriptions of microbial populations, and the formulae for kernels are known in only a few encounter scenarios. Despite this, encounter kernels can guide experimental efforts and provide estimates for parameters in ecological models. This review focuses on encounter kernels describing interactions in aquatic systems.
Review
Microbiology
Sebastian Dan Burz, Senka Causevic, Alma Dal Co, Marija Dmitrijeva, Philipp Engel, Daniel Garrido-Sanz, Gilbert Greub, Siegfried Hapfelmeier, Wolf-Dietrich Hardt, Vassily Hatzimanikatis, Clara Margot Heiman, Mathias Klaus-Maria Herzog, Alyson Hockenberry, Christoph Keel, Andreas Keppler, Soon-Jae Lee, Julien Luneau, Lukas Malfertheiner, Sara Mitri, Bidong Ngyuen, Omid Oftadeh, Alan R. Pacheco, Francois Peaudecerf, Gregory Resch, Hans-Joachim Ruscheweyh, Asli Sahin, Ian R. Sanders, Emma Slack, Shinichi Sunagawa, Janko Tackmann, Robin Tecon, Giovanni Stefano Ugolini, Jordan Vacheron, Jan Roelof van der Meer, Evangelia Vayena, Pascale Vonaesch, Julia A. Vorholt
Summary: Communities of microorganisms are present in all habitats on Earth and play important roles in agriculture, health, and climate. However, the complexity of microbiomes poses challenges in understanding their mechanisms. The N+1/N-1 concept is a systematic approach that aims to dissect microbiome assembly and functioning, and intervene with specific microbial strains, to unravel the structure and function of microbiomes.
MICROBIOLOGY AND MOLECULAR BIOLOGY REVIEWS
(2023)
Article
Physics, Multidisciplinary
Pierre A. Haas, Maria A. Gutierrez, Nuno M. Oliveira, Raymond E. Goldstein
Summary: Recent theoretical work has shown that clonal microbes can stabilize microbial communities by switching between different phenotypes. This switching can be stochastic or in response to environmental factors. The study explores the ecological effects of responsive switching and shows that it can stabilize coexistence, even when stochastic switching does not affect community stability.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Chemistry, Physical
Christophe Raufaste, Simon Cox, Raymond E. Goldstein, Adriana Pesci
Summary: This study investigates the collapse of a catenoidal soap film when the supporting rings are moved beyond a critical separation. By dividing the catenoid with a glass plate, two identical hemicatenoids with a surface Plateau border (SPB) on the plate are formed. The collapse of the hemicatenoids is governed by frictional forces arising from viscous dissipation in the SPBs. Numerical studies confirm the relationship between the frictional force and the capillary number on wet surfaces. This study is significant for understanding the fragmentation of bubbles in highly confined geometries.