The European Physical Journal. E, Soft Matter[JOURNAL]
Sun
200 papers
What is active wetting?
Thiele U
Eur Phys J E Soft Matter · 2026 Jul · PMID 42393398 · Full text
In recent years, the term active wetting has gained some traction in works describing, analyzing, and modeling a wide variety of wetting phenomena, for instance, in the contexts of biomolecular condensates, of cell laye...
In recent years, the term active wetting has gained some traction in works describing, analyzing, and modeling a wide variety of wetting phenomena, for instance, in the contexts of biomolecular condensates, of cell layers or cell aggregates, and of active Brownian particles. The present perspective discusses a coarse classification of wetting phenomena that accounts for this. First, different categories of static and dynamic wetting of passive liquids are briefly introduced, in particular, distinguishing equilibrium wetting, relaxational wetting, driven wetting, and reactive wetting. Second, an overview is given of the various phenomena recently described as active wetting. We conclude by discussing a possible definition of active wetting together with a number of caveats that one might want to keep in mind when using such classifications.
Metallic microresonator spectral modes with inhomogeneously twisted nematic in magnetic field.
Gunyakov VA, Zuev AS, Parshin AM … +4 more , Sutormin VS, Timofeev IV, Zyryanov VY, Shabanov VF
Eur Phys J E Soft Matter · 2026 Jun · PMID 42371370 · Publisher ↗
A common, but not the only method for the spectral resonance shift in a microresonator is to change the cavity's optical path. A fundamentally different approach to separate polarized modes at the fixed optical path cons...
A common, but not the only method for the spectral resonance shift in a microresonator is to change the cavity's optical path. A fundamentally different approach to separate polarized modes at the fixed optical path consists in inhomogeneous twisting of a medium within the cavity, which allows for the creation of high-sensitivity devices such as sensors, filters, microlasers, modulators, phase shifters, etc. An experimental and theoretical study of the polarization and spectral properties of a Fabry-Pérot microresonator formed by a pair of flat metallic mirrors with a planar-oriented nematic liquid crystal layer between them has been carried out. The specific chirality of the liquid crystal structure is induced by a magnetic field in the T-effect regime and is characterized by inhomogeneous twisting and the presence of a plane at the center of the nematic layer where the local director reverses the twist sign. Despite the small resulting deformation, these factors enhance the nonadiabatic propagation of light waves in the resonator, which, in turn, leads to significant anomalous shifts of the polarized resonant modes in the transmittance spectrum. The obtained experimental spectral shifts of the modes are consistent with the data of the numerical simulation using the 4 4 transfer matrix method and are explained by the contribution of the geometric phase, which paves the way to novel topological photonics devices.
Perspective on the paper: GDR MiDi. On dense granular flows.
Herrmann HJ, Luding S
Eur Phys J E Soft Matter · 2026 Jun · PMID 42371312 · Full text
The study "On dense granular flows" by GDR MiDi, published in 2004 in The European Physical Journal E 14, 341-365, stands as a seminal collective work that significantly advanced the understanding of dense granular mater...
The study "On dense granular flows" by GDR MiDi, published in 2004 in The European Physical Journal E 14, 341-365, stands as a seminal collective work that significantly advanced the understanding of dense granular materials. Remarkably, the names of the contributing authors are not listed; only the name of the consortium is given-a brave statement for joint efforts like this!. The GDR Midi (Groupement de Recherche sur les Milieux Divisés) was a CNRS-led consortium of French laboratories. Its mission was to bring together diverse scientific communities-including solid mechanics, fluid mechanics, physics, and geophysics-around the study of granular media, in order to promote collaboration through frequent, informal meetings held typically four times per year (see group photograph of a meeting in Carry Le Rouet in 2005). This approach enabled the identification of key scientific challenges as the need to compare and consolidate data across different configurations, between experiments and simulations, and across different research groups, ultimately inspiring the work that led to the collective GDR Midi paper.
Dynamics of a three-dimensional oil drop driven by a surface acoustic wave over topography.
Fasano M, Li Y, Diez JA … +3 more , Manor O, Cummings LJ, Kondic L
Eur Phys J E Soft Matter · 2026 Jun · PMID 42371268 · Full text
We perform three-dimensional simulations of SAW-driven spreading of silicone oil drops on flat substrates and over solid obstacles. The resulting model takes the form of a three-dimensional long-wave thin-film equation i...
We perform three-dimensional simulations of SAW-driven spreading of silicone oil drops on flat substrates and over solid obstacles. The resulting model takes the form of a three-dimensional long-wave thin-film equation incorporating capillary, gravitational, and SAW-induced acoustic stresses. A key feature of the formulation is a smooth attenuation function that localizes acoustic forcing within the bulk drop while avoiding spurious transverse discontinuities. Comparisons with results of earlier 2D formulations demonstrate qualitatively similar dynamics, albeit the additional spatial dimension permits transverse mass redistribution driven by capillarity, which leads to slower streamwise spreading and slightly lower drop apexes than predicted by 2D models. The model is applied to SAW induced dynamic wetting of flat substrates and solid obstacles and is representative of experimental geometries. Quantitative comparisons with experimental observations show good agreement for front propagation and obstacle climbing dynamics. In particular, improved agreement with the experimentally observed dependence of the liquid climbing time over obstacles on SAW amplitude is obtained when the fully three-dimensional formulation is used.
Resolvability parameters in molecular graphs of antimalarial drugs.
Chidambaram N, Vadivel Y, R S … +1 more , Ravi V
Eur Phys J E Soft Matter · 2026 Jun · PMID 42350735 · Publisher ↗
Chemical graph theory facilitates the understanding of the complex structure of molecules. Researchers can achieve a thorough understanding of the physical science, chemical properties, and bio-organic characteristics of...
Chemical graph theory facilitates the understanding of the complex structure of molecules. Researchers can achieve a thorough understanding of the physical science, chemical properties, and bio-organic characteristics of pharmaceuticals through the calculation of resolvability and topological parameters in drug design. The resolvability constraints for graph constitute a complex domain in which the framework is structured so that each vertex (atom) or edge (bond) denotes a distinct position. This study aims to utilize molecular graph theory to identify specific graph-theoretic parameters associated with the molecular graphs of eight medications used in malaria treatment. This paper presents resolvability parameters, including metric dimension (MD) and edge metric dimension (EMD), for eight medications used in malaria treatment. We demonstrate that the resolvability parameters for the specified drugs are both bounded and constant. This property facilitates molecular identification, verifies graph isomorphism, and functions as a valuable topological descriptor in QSAR/QSPR modeling. Furthermore, it improves chemical database indexing and feature generation for machine learning, facilitating efficient structure-based analysis in drug discovery and material design.
Inertial forces and elastohydrodynamic interaction of spherical particles in wall-bounded sedimentation experiments at low .
Noichl I, Schönecker C
Eur Phys J E Soft Matter · 2026 Jun · PMID 42332213 · Full text
Unsteady, wall-bounded sedimentation of spheres at low particle Reynolds numbers, Re , under the influence of small elastic deformation was investigated experimentally. The complete kinematics of elastic and rigid spher...
Unsteady, wall-bounded sedimentation of spheres at low particle Reynolds numbers, Re , under the influence of small elastic deformation was investigated experimentally. The complete kinematics of elastic and rigid spheres sedimenting from rest at various initial distances from a rigid plane wall in a rectangular duct were measured. Several previously unrecognized phenomena arising from fluid inertia and superimposed elastohydrodynamic effects were identified and analyzed. Among these is an inertial wall attraction, whereby particles migrate toward the wall during the initial acceleration phase. After this initial phase, rigid spheres sedimenting at Re followed behavior consistent with classic wall-lift models, including approximately linear migration away from the wall. In contrast, at smaller Reynolds numbers, Re , both rigid and elastic spheres exhibited persistently unsteady sedimentation, characterized by deceleration despite increasing wall distance. These results enable the formulation of a conceptual framework that classifies near-wall sedimentation regimes according to particle Reynolds number and the position of boundaries relative to the Stokes length scale. For increasing deformability, the unsteady behavior was further modulated by nonlinearities. The observations suggest the presence of an elastohydrodynamic memory effect arising from the coupling of fluid inertial forces with particle deformability. The experimental findings are supported by computational fluid dynamics simulations that provide qualitative insight into the evolving flow field. Overall, the results demonstrate that classic assumptions commonly applied to particle sedimentation in creeping flows break down in the presence of nearby boundaries and reveal a counterintuitive trend: as the particle Reynolds number decreases, fluid inertia can play an increasingly important role in governing particle motion near walls. The proposed conceptual framework may therefore aid the interpretation of the near-wall dynamics of deformable microplastic particles, for which comparable material properties and flow regimes are encountered in environmental and wastewater flows.
Semi-analytical modeling and simulation of human red blood cell deformation under non-linear strain.
Bhabhor GD, Bhatt R, Anand A … +1 more , Lad KN
Eur Phys J E Soft Matter · 2026 Jun · PMID 42323474 · Publisher ↗
The study of red blood cell (RBC) deformability remains an active area of research due to its linkage to health and normal physiological functions of RBCs in the circulatory system. RBC deformability is commonly analyzed...
The study of red blood cell (RBC) deformability remains an active area of research due to its linkage to health and normal physiological functions of RBCs in the circulatory system. RBC deformability is commonly analyzed using force-based experimental and theoretical approaches. Complementary to these methods, geometric descriptions of RBC shape provide insight into curvature redistribution and bending energetics independent of explicit constitutive modeling. In this work, we present a semi-analytical, surface-based framework to study RBC deformation under axial stretching by imposing an affine geometric strain on a triangulated biconcave membrane, with volume conservation enforced throughout. Linear strain and a non-linear Hencky-type strain are compared. While linear strain reproduces experimental trends only for small deformations, nonlinear strain yields global shape variations-axial and transverse diameters and elongation index-that are consistent with reported optical tweezers data over a wide deformation range. The surface formulation enables detailed mapping of Gaussian and mean curvature redistribution during elongation. Evaluation of the Helfrich bending energy, including spontaneous curvature treated as an effective geometric parameter, yields energetically consistent values when non-linear strain is employed. Analysis of the curvature-bending energy of the RBC subjected to axial stretching suggests that nonlinear strain and spontaneous curvature should be the primary considerations to ensure that the membrane bending energy remains within the range of 10-100 eV during RBC biomechanical deformation. The framework does not resolve force balance or membrane constitutive behavior, but provides a computationally efficient geometric surrogate linking imposed deformation to curvature and bending energetics.
Avalanches in the random organization model with long-range interactions.
Jocteur T, Martens K, Mari R … +1 more , Bertin E
Eur Phys J E Soft Matter · 2026 Jun · PMID 42322493 · Publisher ↗
Oscillatory sheared suspensions, when observed stroboscopically, exhibit a reversible-irreversible transition as a function of the strain amplitude, which is an absorbing phase transition, separating diffusive states on...
Oscillatory sheared suspensions, when observed stroboscopically, exhibit a reversible-irreversible transition as a function of the strain amplitude, which is an absorbing phase transition, separating diffusive states on the irreversible side from absorbing states on the reversible side. So far studies of this transition focused on global quantities, e.g., quantifying the irreversibility on the one side of the transition or the time to reach a reversible state on the other side. Here, inspired by depinning-type transitions, we focus on intermittent dynamics close to the transition. We perform simulations of a modified Random Organization Model (ROM), a minimal particle model which we recently adapted to take into account the generic presence of long-range interactions mediated by the fluid, taking the power-law decay exponent as an additional control parameter of the model. We show that at the absorbing phase transition, this model displays power-law distributed avalanches. We characterize the avalanche statistics in terms of avalanche size, duration and number of particles involved, and we determine the associated exponents. By varying the exponent , the fractal dimension of avalanches crosses space dimension d, inducing a qualitative change of the spatial structure of avalanches, from compact avalanches when interactions have a short range, to sparse avalanches when interactions are long-ranged. Finally, we characterize the clusters within the avalanches, which we also find to be power-law distributed.
Vector nematodynamics with symmetry-driven energy exchange.
Pismen LM
Eur Phys J E Soft Matter · 2026 Jun · PMID 42307657 · Full text
We review inadequacy of existing nematodynamic theories based on Onsager's near-equilibrium relations and suggest a novel way of establishing relations between nematic orientation and flow, based on the local symmetry be...
We review inadequacy of existing nematodynamic theories based on Onsager's near-equilibrium relations and suggest a novel way of establishing relations between nematic orientation and flow, based on the local symmetry between simultaneous rotation of nematic alignment and flow, which establishes energy and momentum exchange between the two without reducing the problem to near-equilibrium conditions. This approach, applied in the framework of the vector-based theory with a variable modulus, involves antisymmetric interactions between nematic alignment and flow. It avoids spurious instabilities in the absence of active inputs and elucidates their cause.
Drop volume effect on the advancing macroscopic contact angle.
Issa R, Benabdelhalim H, Medale M … +1 more , Brutin D
Eur Phys J E Soft Matter · 2026 Jun · PMID 42234346 · Publisher ↗
We investigate the influence of drop volume on partial wetting of sessile drops on a horizontal solid substrate for up to large Bond numbers, considering water on both polymethyl methacrylate (PMMA) and aluminum-coated s...
We investigate the influence of drop volume on partial wetting of sessile drops on a horizontal solid substrate for up to large Bond numbers, considering water on both polymethyl methacrylate (PMMA) and aluminum-coated substrates, as well as glycerol on PMMA. The horizontal orientation of the substrate, along with methods for creating sessile drops, facilitated the rotational symmetry of drops to perform controlled and reproducible experiments. In particular, we explore the manner in which the statistic macroscopic contact angle (MCA) depends on the sessile drop volume or related Bond numbers, whether the drop is injected via a syringe positioned above the substrate (DSA30 Krüss equipment) or from below the substrate through a tiny hole drilled in it. In both cases, experimental results exhibit that as the drop volume is increased spanning Bond numbers in the range [0.1-14], the contact line advances on the substrate and the MCA significantly decreases down to an asymptotic value.
Giant nonequilibrium fluctuations in dilute and semidilute polymer solutions subjected to large temperature gradients.
Kantelhardt J, Zapf D, Köhler W
Eur Phys J E Soft Matter · 2026 Jun · PMID 42230401 · Full text
Shadowgraph experiments have been performed on giant nonequilibrium fluctuations in solutions of polystyrene in toluene with polymer molar masses between 2.1 and 90.9 kg/mol and mass fractions ranging from 0.002 up to 0....
Shadowgraph experiments have been performed on giant nonequilibrium fluctuations in solutions of polystyrene in toluene with polymer molar masses between 2.1 and 90.9 kg/mol and mass fractions ranging from 0.002 up to 0.6. Due to the large Soret coefficient of the polymer and the applied temperature difference of 50 K, a linear model is not sufficient to describe the time-dependent and static structure functions. Nonlinearities stemming mainly from the highly nonlinear concentration profile, as well as from the temperature and concentration dependence of various thermophysical parameters, are taken into account using a previously developed layer model. This model enables a detailed analysis of the signal generation within the shadowgraph cell. The thermal structure function mainly emerges from the hot top plate. For short polymer chains and/or low concentrations, the solutal structure function is dominated by the cold side. However, due to the complicated interplay between the Soret effect, the viscosity, and the gravitational quench, this can change for long chains and high concentrations, with the strongest solutal signal emerging from the hot side. Situations involving a non-monotonous layer sequence are also possible. The simulated structure functions agree reasonably with experimental data.
Thermodiffusion and thermo-osmosis in thin membranes with slit pores.
Hafskjold B, Kjelstrup S
Eur Phys J E Soft Matter · 2026 Jun · PMID 42223849 · Full text
Waste heat sources are potentially useful for component separation in fluid mixtures. To better understand how thermal driving forces can contribute to separation, we have investigated the Soret balances of forces for th...
Waste heat sources are potentially useful for component separation in fluid mixtures. To better understand how thermal driving forces can contribute to separation, we have investigated the Soret balances of forces for thermodiffusion and thermo-osmosis. A set of two-component fluid isotope mixtures with mass ratio has been investigated in membranes with molecular-sized pores. Numerical support generated by molecular dynamics simulations is achieved for two models; one for the Soret coefficient, , and one for the thermo-osmotic coefficient, , where is a parameter for the fluid-membrane interactions, refers to a difference across the membrane, H is the bulk fluid enthalpy, and T is the temperature. In these formulas are system-specific constants. The results apply to Lennard-Jones/spline isotope mixtures of mass ratios , with thermally insulating membrane materials, and component-specific fluid-pore interactions. The results give information about how the Soret balances depend on membrane properties, which potentially can be used to tailor membranes for efficient separation.
A study of the interference colors of the microscopic textures simulated along the lyotropic phase sequence: cholesteric discotic-cholesteric biaxial-unwound cholesteric calamitic.
Lüders DD, Akpinar E, Delmanoco GE
Eur Phys J E Soft Matter · 2026 Jun · PMID 42223814 · Full text
The interference colors of the microscopic textures, observed under a polarized microscope for the oriented cholesteric discotic (Ch)-cholesteric biaxial (Ch)-unwound cholesteric calamitic (N) phases sequence in the pres...
The interference colors of the microscopic textures, observed under a polarized microscope for the oriented cholesteric discotic (Ch)-cholesteric biaxial (Ch)-unwound cholesteric calamitic (N) phases sequence in the presence of a magnetic field, were studied in this work. The referred textures were interpreted from both experimental and theoretical views. The lyotropic nematic host mixtures consisted of potassium laurate (KL), 1-undecanol (unDeOH), potassium sulphfate (KSO), and water (HO). The chiral guest molecule brucine was added to the host nematic mixture to induce the cholesteric phases. The refractive indices and birefringences of the lyotropic samples were measured along the nematic calamitic (N)-nematic biaxial (N)-nematic discotic (N) phases sequence as a function of temperature, and they were used to simulate the stripe textures of the oriented cholesteric phases, Ch and Ch, theoretically. It was shown that the experimental and simulated results are in good agreement with each other.
Cruising and jumping: the effect of microplastics on the swimming behavior of copepods measured by 3D Lagrangian particle tracking velocimetry.
Michalec FG, Praud O, Lorite-Diez M … +3 more , Cazin S, Souissi S, Climent E
Eur Phys J E Soft Matter · 2026 May · PMID 42201637 · Full text
Calanoid copepods are key components of marine and estuarine food webs. Exposure to various classes of pollutants induces changes in their swimming behavior. This raises concerns about potential effects on critical proce...
Calanoid copepods are key components of marine and estuarine food webs. Exposure to various classes of pollutants induces changes in their swimming behavior. This raises concerns about potential effects on critical processes such as feeding, mating, predator avoidance and vertical migration. The effect of pollution by microplastics is not well known. We investigated in a large experimental tank the effects of the smallest size fraction of microplastics on the swimming behavior of the estuarine copepod Eurytemora affinis. Because the motion of zooplankton is intrinsically linked to that of the ambient fluid, we recorded copepods moving freely in calm water and in grid-generated turbulence to recreate some of the hydrodynamic conditions they experience in their natural environment. Using an advanced implementation of 3D Lagrangian particle tracking velocimetry, we simultaneously measured copepod trajectories and the surrounding flow field at high temporal resolution. In calm water, copepods alternated between periods of cruising and sudden relocation jumps. In turbulence, copepod motion was dominated by transport by the flow, yet jumps allowed copepods to deviate from the flow streamlines. The measurement of the relative velocity of copepods with respect to the underlying flow enabled us to characterize the statistics of these jumps. Turbulence significantly increased jump frequency without modifying their amplitude or duration. Following a 12-hour exposure to polyethylene fragments at 300 g/L, copepods showed increased jump frequency in calm water corresponding to 40 % increase in energetic cost. In contrast, exposure to microplastics produced weak additional effects on swimming behavior under turbulent conditions. These results confirm the existence of an active response to turbulence in E. affinis and are consistent with a hyperactive behavior triggered by exposure to microplastic pollution.
Modeling the heat of formation of indium telluride via graph entropy descriptors and curve fitting techniques.
Ahmed W, Farzeen A, Ali K … +2 more , Zaman S, Ullah A
Eur Phys J E Soft Matter · 2026 May · PMID 42141347 · Publisher ↗
This study presents an extensive graph-theoretic analysis of the thermodynamic properties of indium telluride (InTe). We analyze the significant relationship between the molecular structure of InTe and its macroscopic be...
This study presents an extensive graph-theoretic analysis of the thermodynamic properties of indium telluride (InTe). We analyze the significant relationship between the molecular structure of InTe and its macroscopic behavior through the application of graph entropy, a fundamental metric in information theory and statistical thermodynamics. In this framework, the chemical structure is depicted as a graph, with atoms as vertices and chemical bonds as edges. We calculate a set of topological indices for InTe, a material that is very useful in thermoelectrics, phase-change memory, and infrared optics. These indices encode the material's structural connectivity in numbers. These indices are used to figure out a range of graph entropies, which measure how complex and information-rich the molecular lattice is. The main part of this work shows strong quantitative links between these graph entropies and important thermodynamic properties, such as heat capacity and heat of formation. We use suitable quadratic surface-fitting models that show exactly how these thermodynamic responses depend on pairs of graph entropies in a nonlinear way. All computational modeling and analysis are conducted to enhance statistical fit, guaranteeing that the chosen models deliver the most dependable predictive capability for comprehending and anticipating the material's stability and thermal characteristics.
Entropy-weighted topological descriptors in QSPR modeling of antituberculosis drugs.
Li X, Kanwal S, Butt HA
Eur Phys J E Soft Matter · 2026 May · PMID 42141329 · Publisher ↗
In this study, we develop quantitative structure-property relationship (QSPR) model using entropy-weighted topological descriptors to predict the physicochemical properties of antituberculosis drugs. The molecular struct...
In this study, we develop quantitative structure-property relationship (QSPR) model using entropy-weighted topological descriptors to predict the physicochemical properties of antituberculosis drugs. The molecular structures of fifteen drugs used to treat tuberculosis were taken from PubChem, and their conventional degree-based descriptors were enhanced via Shannon entropy to account for both structural magnitude and distributional irregularity. These entropy-augmented indices were incorporated into quadratic, cubic, exponential, and logarithmic regression models to describe structure-property relationships. Model validation was performed using unsupervised (Entropy-Property Concordance Index, EPCI) and supervised (Local Regression Concordance, LRC) methods. The results demonstrate that entropy-weighted descriptors significantly improve interpretability, predictive accuracy, and structural validation in QSPR modeling. This approach offers a robust computational framework that can be extended to the rational design and property prediction of macrocyclic ligands and supramolecular assemblies, supporting advances in host-guest chemistry and targeted drug delivery systems.
Macroscopic emulsion drops formed through limited coalescence.
Langevin D
Eur Phys J E Soft Matter · 2026 May · PMID 42118502 · Full text
This short paper is a perspective article related to the seminal paper: S. Arditty, C. P. Whitby, B. P. Binks, V. Schmitt & F. Leal-Calderon "Some general features of limited coalescence in solid-stabilized emulsions" pu...
This short paper is a perspective article related to the seminal paper: S. Arditty, C. P. Whitby, B. P. Binks, V. Schmitt & F. Leal-Calderon "Some general features of limited coalescence in solid-stabilized emulsions" published in 2003 (Arditty et al. in Eur. Phys. J. E 12:355, 2003). I will first briefly recall the work described in this paper and discuss some of the developments that followed its publication. This will include comparisons with different coalescence mechanisms, together with comparisons with surfactant-stabilized emulsions and with particle-stabilized foams. I will end with a few comments on the state of the field of research and on future directions.
Role of wing surface morphology of the Indian carpenter bee in self-cleaning and dew formation.
Narhe R
Eur Phys J E Soft Matter · 2026 May · PMID 42104038 · Publisher ↗
We studied the surface morphology (micro- plus nanostructure) of Indian carpenter bee wings. In comparison with the Stenocara beetle's surface morphology or the lotus leaf surface morphology, the Indian carpenter bee win...
We studied the surface morphology (micro- plus nanostructure) of Indian carpenter bee wings. In comparison with the Stenocara beetle's surface morphology or the lotus leaf surface morphology, the Indian carpenter bee wing shows a different type of surface morphology. It is observed that the two-tire surface morphology of the wings plays a key role in controlling wettability. The equilibrium contact angle (θ) and contact angle hysteresis (Δθ) measurement revealed that the carpenter bees' wings behave as superhydrophobic and self-cleaning for large water drops. Small drops formed by condensation nucleate in microchannels and ridges, grow through condensation and coalescence, and eventually become larger Wenzel or Wenzel-Cassie-Baxter type drops that lose their superhydrophobicity and self-cleaning property. Growth dynamics of condensed water drops on the wing surface show two distinguishing growth laws < R > ~ t, α = 0.41 ± 0.03 in the initial state and < R > ~ t, α = 0.99 ± 0.03 in the self-similar (coalescence-dominated) state with maximum surface coverage ≃ 0.45.
Human lungs fluid mechanics: an overview of current modelling techniques.
Romanò F
Eur Phys J E Soft Matter · 2026 Apr · PMID 42053866 · Full text
Fluid mechanics governs numerous physiological processes in the respiratory system, influencing airflow dynamics, particle transport and aerosol formation, airway stability, mucus transport, surfactant mechanics, and pul...
Fluid mechanics governs numerous physiological processes in the respiratory system, influencing airflow dynamics, particle transport and aerosol formation, airway stability, mucus transport, surfactant mechanics, and pulmonary oedema. Over the past decades, engineers, physicists, and biomedical scientists have developed a wide range of models to describe these processes across multiple spatial and temporal scales. This paper provides an integrated overview of current modelling techniques in pulmonary fluid mechanics, emphasizing the multiscale and multiphysics nature of the lung. After discussing the principal challenges in simulating the mechanics of human lungs, we review the hierarchy of modelling approaches, from first-principle continuum formulations to reduced-order and data-driven models. We then explore strategies for coupling these models and conclude with a perspective on future directions, including the need for benchmark cases and clinically robust indicators for model validation.
Thermal and solutal capillary effects in tear film dynamics.
Kumawat TC, Shah K
Eur Phys J E Soft Matter · 2026 Apr · PMID 41995778 · Publisher ↗
An analytical and numerical study is carried out for the stability of a thin tear film considering a single-layered model. The mass, momentum, and energy equations are simplified under the lubrication approximation to ob...
An analytical and numerical study is carried out for the stability of a thin tear film considering a single-layered model. The mass, momentum, and energy equations are simplified under the lubrication approximation to obtain nonlinear partial differential spatiotemporal evolution equations for the film height and surfactant concentration. These evolution equations involve various physical mechanisms such as thermo- and solutocapillary stresses, van der Waals forces, surface tension forces, and slip at the corneal surface. Linear stability analysis reveals that solutocapillary stresses enhance the stability of the tear film by driving fluid from thicker to thinner regions. The thermocapillary stresses are found to enhance the instability, where the fluid is driven from a thinner (low surface tension) region to a thicker (high surface tension) region. Convective cooling due to cold wind flow also affects the growth rate of perturbations, with higher convection leading to a higher growth rate. The solutocapillary stresses dominate over the thermocapillary stresses beyond a certain critical value of the solutal Marangoni number. This critical threshold decreases with increasing Péclet number, indicating that the influence of solutocapillary effects becomes more pronounced under stronger advective transport. Numerical computations are carried out and show that the nonlinear stability results are in good agreement with those obtained from linear stability analysis. Furthermore, the computations reveal that the rupture time decreases with increasing thermal Marangoni number and slip coefficient, whereas it increases with the solutal Marangoni number.
About
- Frequency
- Sun
- Papers found
- 200
- RSS feed
- Subscribe