Article
Mechanics
Bhargav Rallabandi, Jens Eggers, Miguel Angel Herrada, Howard A. Stone
Summary: The study investigates the motion of a rigid, axisymmetric intruding object through an elastic tube filled with viscous fluid, analyzing the relationship between lubrication effects and various factors. It is found that the drag force on the intruding object depends on the slope of its surface at the entrance to the thin fluid film, scaling as the square root of the relative speed.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Carlos G. Hernandez, Qiang Yang, Yongyun Hwang
Summary: The generalized quasilinear approximation is applied to turbulent channel flow to study the energy transfer mechanism. Comparisons with the traditional quasilinear model show that the generalized quasilinear approximation performs better in simulating high Reynolds number flows. It is proposed that the energy scattering mechanism is related to the linearized equations.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Thermodynamics
Huaiji Bi, Jiayao Yang, Chunlin Chen, Baojun Luo
Summary: In this study, the heat transfer and flow characteristics of intermittent oscillating flow in a tube were numerically investigated. The results showed that compared to sinusoidal oscillating flow, the total heat transfer coefficient was 14.6% lower and the pressure drop was 0.83% higher in intermittent oscillating flow. The pressure drop curves were similar in both flows, and the velocity distributions were also comparable.
APPLIED THERMAL ENGINEERING
(2023)
Article
Mechanics
Wai Hong Ronald Chan, Perry L. Johnson, Parviz Moin
Summary: This study investigates the generation mechanism of bubbles during wave-breaking processes, exploring the locality feature of bubble-mass cascade.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Thermodynamics
Minjie Yu, Feng Xin, Xiaotian Lai, Hui Xiao, Zhichun Liu, Wei Liu
Summary: The novel constructal bifurcation regenerator developed based on the constructal concept reduces flow resistance in Stirling regenerators. Through CFD analysis, the regenerator's pressure drop and heat transfer characteristics were studied, leading to the establishment of correlation equations to predict performance. Compared to other regenerators, the constructal bifurcation regenerator showed lower flow resistance and moderate heat transfer, ultimately improving the overall performance of Stirling engines.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Zhou Yihui, Guo Jiangtao, Huang Zhaofeng, Gao Feng, Liu Zhijun, Hu Dapeng
Summary: This paper designs and establishes the core component of the industrial-scale gas wave refrigerator (GWR), the 600 mm double-opening pressure oscillation tube, and its visualization investigation platform. The high-speed multi-schlieren splicing technology is proposed to obtain the quantitative description of the density gradient field in the gas wave oscillation tube, which is validated using the two-dimensional Euler equation. The experimental results show that the shockwave Mach number increases with the increasing pressure ratio or rotating speed.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2023)
Article
Engineering, Mechanical
Ji Lang, Liyun Wang, Qianhong Wu
Summary: This theoretical study discusses the transient squeezing flow through a thin porous gap driven by an oscillating boundary, considering viscous, inertial, and Darcy effects. It reveals that increasing the squeezing depth enhances the oscillation of the velocity profiles due to the alternating dominance of viscous and inertial effects. The presence of porous media stabilizes the fluid field, showcasing potential applications in fields such as biomedical and industrial processes.
TRIBOLOGY INTERNATIONAL
(2021)
Article
Multidisciplinary Sciences
Massimo Tessarotto, Claudio Cremaschini
Summary: This article considers the implications of the principles of general and manifest covariance, along with the objectivity principle, in establishing a DeDonder-Weyl-type Hamiltonian variational formulation for classical general relativity. By analyzing the Einstein-Hilbert variational principle, it is shown that only synchronous variational principles allow for the construction of fully 4-tensor Lagrangian and Hamiltonian theories of this kind. Additionally, the potential validity of an extended Hamiltonian formulation that includes the Ricci tensor as Lagrangian variables is investigated, and it is shown to occur when the classical cosmological constant is non-zero.
Article
Green & Sustainable Science & Technology
Lin Cui, Siming Zheng, Yongliang Zhang, Jon Miles, Gregorio Iglesias
Summary: This paper introduces a hybrid wave energy converter OWCOB, which combines oscillating water column and oscillating buoy to capture wave energy. By establishing an analytical model and conducting sensitivity analysis, it is found that OWCOB outperforms standalone OWCs and OBs, particularly in terms of frequency bandwidth for wave power capture.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2021)
Article
Public, Environmental & Occupational Health
Elizabeth A. Wood, Sarah L. Collins, Savanah Mueller, Nichole E. Stetten, Mona El-Shokry
Summary: Collaborative online international learning (COIL), also known as virtual exchange, is an effective approach in higher education for offering intercultural competence through experiential learning. This study evaluates the effectiveness of a virtual exchange implemented in an undergraduate global public health course and identifies the impact of personal backgrounds and experiences on students' perception of the exchange. Despite course-related barriers, students acknowledged the improvement of their intercultural competence and knowledge of course content through the virtual exchange.
FRONTIERS IN PUBLIC HEALTH
(2022)
Article
Thermodynamics
Lilin Chu, Yulong Ji, Zhang Liu, Chunrong Yu, Zhenting Wu, Zongyu Wang, Yunxiao Yang, Xin Yang
Summary: The effects of the bend curvature radius and tube diameter on the heat transfer performance of a three-dimensional coil oscillating heat pipe (3DCOHP) were experimentally studied. The results showed that reducing the bend curvature radius and increasing the tube diameter can enhance the formation of unidirectional flow and significantly improve the heat transfer performance. The reason for the unidirectional flow in asymmetric heating mode was also analyzed.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Chemistry, Applied
Abdulmonem Fetyan, Bronston P. Benetho, Musbaudeen O. Bamgbopa
Summary: The high costs of the currently used membranes in VRFBs contribute to the price of the VRFB systems and limit their market share. A proposed centred and double-strip membrane coverage showed promising performance and the membrane size can be comfortably reduced by up to 20% without severe efficiency or discharge capacity loss. Long-term cycling with 80% centred membrane coverage showed improved capacity retention and only slight differences in capacity and energy efficiency compared to fully covered-membrane cell. These results hold great promise for the development of cheap RFB stacks and new cell designs.
JOURNAL OF ENERGY CHEMISTRY
(2023)
Article
Mechanics
Sandeep Kumar, Bhupendra K. K. Gandhi
Summary: Axial water injection method is used to mitigate the rotating vortex rope (RVR) and associated pressure pulsations in the draft tube of a Francis turbine. The runner cone is modified to install a nozzle for injecting water at different flow rates. Spectral analysis shows a reduction in pulsation amplitudes and improvement in pressure recovery with water injection. The most effective injection ratio is found to be 1% and 1.25%, while higher injection ratios cause pulsations near the draft tube bend.
Article
Thermodynamics
Ahmad Shafee, M. Jafaryar, Ammar Alsabery, Aurang Zaib, Houman Babazadeh
Summary: The study shows that inserting a helical device can induce swirl intensity and benefit convective mode. Increasing the width of the helical inserts can enhance temperature gradient and secondary flow, while raising the inlet velocity generates higher turbulent intensity through increased interaction of nanomaterial with solid surfaces.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Article
Physics, Particles & Fields
Lakshya Bhardwaj
Summary: A class of 5d superconformal field theories can be constructed by integrating out BPS particles from 6d SCFTs compactified on a circle. The flavor symmetry of these 5d SCFTs can be extracted using geometric engineering in M-theory.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Editorial Material
Mechanics
Oliver E. Jensen
Summary: The article explores the characteristics of slender viscous and elastic-viscoplastic sheets, focusing on regimes where bending deformations dominate stretching. The results reveal a rich phenomenology and provide new theoretical tools for probing thin layers of soft materials.
JOURNAL OF FLUID MECHANICS
(2021)
Book Review
Mechanics
Matthias Heil
JOURNAL OF FLUID MECHANICS
(2021)
Editorial Material
Multidisciplinary Sciences
Oliver E. Jensen
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Mechanics
Joao Fontana, Anne Juel, Nico Bergemann, Matthias Heil, Andrew L. Hazel
Summary: We conducted a theoretical study on the interaction between a two-phase fluid and a structure, where air is driven at constant volume flux into a liquid-filled Hele-Shaw channel whose upper boundary is an elastic sheet. The study revealed various instabilities in the interface propagation modes as the level of initial collapse increases, leading to different finger patterns on the curved interface. The model shows a complex solution structure with stable and unstable, steady and time-periodic modes, providing good agreement with experimental data when accounting for the presence of liquid films on the channel walls.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Eleanor C. Johnstone, Andrew L. Hazel, Oliver E. Jensen
Summary: In this study, we present theoretical and numerical results that show the sensitivity of the shape of a static meniscus in a rectangular channel to localized geometric perturbations in the form of narrow ridges and grooves on the channel walls. Our findings reveal that small-amplitude perturbations can induce a change in pressure difference across the meniscus, resulting in long-range curvature of its contact line. We also propose a method to engineer contact lines with prescribed patterns using suitable combinations of ridges and grooves.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Materials Science, Multidisciplinary
Giulia L. Celora, Matthew G. Hennessy, Andreas Munch, Barbara Wagner, Sarah L. Waters
Summary: In this study, a novel phase-field theory based on non-equilibrium thermodynamics is proposed to investigate the macroscopic deformations and internal structure of a polyelectrolyte gel in an ionic solution. The study reveals that the regulation of phase separation in the gel-bath system depends on the competition between the Debye and Kuhn lengths. Depending on the ion concentration in the surrounding bath, the gel can undergo either swelling or deswelling through front propagation or combined with spinodal decomposition.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Mechanics
James D. Shemilt, Alexander Horsley, Oliver E. Jensen, Alice B. Thompson, Carl A. Whitfield
Summary: This study investigates the instability of the mucus layer lining the airway wall by deriving evolution equations for its thickness. The results show that increasing the capillary Bingham number reduces the final deformation of the layer and increases the critical layer thickness required to form a liquid plug.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Multidisciplinary Sciences
George F. Price, Igor L. Chernyavsky, Oliver E. Jensen
Summary: We investigate the transport of solute past isolated sinks in a bounded domain dominated by advection, and evaluate the effectiveness of homogenization approximations when the sinks are randomly distributed. We find that corrections to the approximations can be non-local, non-smooth, and non-Gaussian depending on the physical parameters and the compactness of the sinks. In one dimension, solute distributions develop a staircase structure, while in two and three dimensions, they are near-singular at each sink. We approximate these corrections using a moment-expansion method and test our predictions against simulations.
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Physiology
Carl A. Whitfield, Alexander Horsley, Oliver E. Jensen, Felix C. Horn, Guilhem J. Collier, Laurie J. Smith, Jim M. Wild
Summary: This study demonstrated the prediction of ventilation distributions from MBW data using a mathematical model, and compared these predictions with ventilation MRI data, showing strong correlation and agreement. The Bayesian method utilized in this study reduces acquisition time required for clinical decision making.
RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY
(2022)
Article
Biophysics
Oliver E. Jensen, Christopher K. Revell
Summary: The vertex model is widely used to simulate the mechanical properties of multicellular tissues. This study focuses on the stress attributed to tricellular junctions and examines its antisymmetric component and associated couple stresses, which characterize the response of individual cells to in-plane bending deformations. The results highlight the contribution of small-scale defects and boundary layers to global stress patterns.
BIOMECHANICS AND MODELING IN MECHANOBIOLOGY
(2023)
Article
Mathematics, Applied
D. J. Netherwood, R. J. Whittaker
Summary: We investigate the small-amplitude deformations of a long thin-walled elastic tube with an initially axially uniform elliptical cross-section. At leading order, its deformations are governed by a single partial differential equation (PDE) for the azimuthal displacement. Instead of making ad hoc approximations, we write the azimuthal displacement as a sum over the azimuthal eigenfunctions and derive an uncoupled system of linear PDEs with constant coefficients for the amplitude of the azimuthal modes. This method leads to a significant simplification and a more accurate solution when calculating contributions from the higher-order azimuthal modes.
QUARTERLY JOURNAL OF MECHANICS AND APPLIED MATHEMATICS
(2023)
Article
Chemistry, Physical
Haolin Li, Aidan Retallick, Anne Juel, Matthias Heil, Draga Pihler-Puzovic
Summary: In this study, the effect of inflation on the wrinkling of thin elastic membranes in a commonly used device for creating microchannels was investigated. Through a combination of experiments and numerical simulations, it was found that as swelling progresses, the membrane undergoes two distinct instabilities, first developing small-amplitude wrinkles and then transitioning into large-amplitude folds, whose morphology can be controlled by the degree of pre-inflation.
Meeting Abstract
Respiratory System
J. Shemilt, A. Horsley, O. Jensen, A. Thompson, C. Whitfield
EUROPEAN RESPIRATORY JOURNAL
(2022)
Article
Biology
Qi Zhou, Kerstin Schirrmann, Eleanor Doman, Qi Chen, Naval Singh, P. Ravi Selvaganapathy, Miguel O. Bernabeu, Oliver E. Jensen, Anne Juel, Igor L. Chernyavsky, Timm Kruger
Summary: Research has shown that the microhemodynamics of a vascular network, supported by its interconnected structure, plays a crucial role in blood flow patterns. Structural disorder in extravascular media can impact blood flow dynamics. Three main effects were observed in the study: the apparent viscosity of blood increases with structural disorder, the presence of red blood cells dynamically alters flow distribution, and moderate structural disorder can promote more uniform red blood cell distribution.
Article
Engineering, Biomedical
Qi Zhou, Eleanor Doman, Kerstin Schirrmann, Qi Chen, Elizabeth A. Seed, Edward D. Johnstone, P. Ravi Selvaganapathy, Anne Juel, Oliver E. Jensen, Miguel O. Bernabeu, Timm Krueger, Igor L. Chernyavsky
Summary: The placenta is a crucial interface between the mother and her developing fetus, yet its complex structure and its relation to pregnancy pathologies are still poorly understood. Recent advances in cross-disciplinary imaging and modeling have provided new methods and tools for studying placental microhemodynamics. Future development requires optimization of computational architecture, integration of microhemodynamics with solute transport, and addressing the lack of clear scale separation across the placental architecture.
CURRENT OPINION IN BIOMEDICAL ENGINEERING
(2022)
