International Journal of Multiphase Flow最新文献

{"title":"On the particle clustering in the wake of a normal flat plate: Influence of inflow boundary conditions","authors":"Peddi Harishteja ,&nbsp;Deekshith I. Poojary ,&nbsp;Cristian Marchioli ,&nbsp;Vagesh D. Narasimhamurthy","doi":"10.1016/j.ijmultiphaseflow.2026.105623","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105623","url":null,"abstract":"<div><div>In this study, we examine the effect produced by different inflow conditions on the behavior of inertial particles within the wake produced by a normal flat plate. To this aim, we perform Euler–Lagrangian simulations of the particle-laden wake, using the in-house solver MGLET-LaParT. An unsteady wake with a Reynolds number of 60 is considered, and four inflow conditions are examined: uniform inflow, planar shear inflow, and addition of inflow turbulence to both uniform and planar shear. Particles with different Stokes numbers (<span><math><mrow><mi>S</mi><mi>t</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>1</mn><mo>,</mo><mn>1</mn><mo>,</mo><mn>5</mn></mrow></math></span>, and 10) are analyzed. Particle dispersion, voids, and connected clusters are quantified using Voronoï tessellations and Minkowski functionals, along with statistics of concentration, particle velocity, and slip velocity. The results reveal a distinct influence of both inertia and inflow conditions. Uniform inflow produces symmetric lateral accumulation, whereas planar shear induces asymmetry and enhances wake centerline concentration. With the addition of inflow turbulence to planar shear, the particles at the periphery of the voids created by vortices become more dispersed and irregular, particularly at the highest Stokes number (<span><math><mrow><mi>S</mi><mi>t</mi><mo>=</mo><mn>10</mn></mrow></math></span>). Cluster formation is analyzed by backtracking the particles that eventually form clusters. Further analysis indicates that cluster morphology depends on particle inertia: Elongated clusters are found at <span><math><mrow><mi>S</mi><mi>t</mi><mo>=</mo><mn>1</mn></mrow></math></span>, the largest compact clusters at <span><math><mrow><mi>S</mi><mi>t</mi><mo>=</mo><mn>5</mn></mrow></math></span>, and diffuse clusters at <span><math><mrow><mi>S</mi><mi>t</mi><mo>=</mo><mn>10</mn></mrow></math></span>. Inflow conditions modulate cluster coherence, particularly at higher Stokes numbers. The probability distributions of normalized cluster areas exhibit power-law decay, highlighting fractal, scale-free organization dominated by intermediate-sized clusters. We believe these findings provide a quantitative framework linking inflow, inertia, and wake dynamics, offering benchmarks for predictive multiphase flow models.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105623"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A filter-dependent granular temperature model from large-scale CFD-DEM data","authors":"L. Rosenberg ,&nbsp;W.D. Fullmer ,&nbsp;S. Beetham","doi":"10.1016/j.ijmultiphaseflow.2026.105625","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105625","url":null,"abstract":"<div><div>The computational study of strongly-coupled, gas–solid flows at scales relevant to most environmental and engineering applications requires the use of ‘coarse-grained’ methodologies such as the two-fluid model, particle-in-cell approach or the multiphase Reynolds Averaged Navier–Stokes equations. While these strategies enable computations at desirable length- and time-scales, they rely heavily on models to capture important flow physics that occur at scales smaller than the mesh. To date, the models that do exist are based on a limited set of flow conditions, such as very dilute particle phase. To this end, we leverage a large-scale repository of CFD-DEM data to develop filter-size dependent models for the mean variance in particle volume fraction, a quantity commonly used to assess the degree of clustering, and the granular temperature, a key quantity for accurately predicting gas–solid flows. Because of its filter-size dependence, the granular temperature model can be directly translated to coarse-grained approaches and tied directly to grid size.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105625"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiphase flow impressions: Selected poster contributions from ICMF 2025","authors":"Manuel Moriche,&nbsp;S. Balachandar,&nbsp;Alfredo Soldati","doi":"10.1016/j.ijmultiphaseflow.2025.105594","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105594","url":null,"abstract":"","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105594"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the modelling of the wall-void layer in high-pressure, subcooled flow boiling","authors":"Silvia Nauer,&nbsp;Joel-Steven Singh,&nbsp;Djamel Lakehal","doi":"10.1016/j.ijmultiphaseflow.2026.105609","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105609","url":null,"abstract":"<div><div>In the context of the wall heat flux partitioning approach, we propose a new modelling route for high-pressure, subcooled flow boiling, which we simplify by removing the quenching part. Examining the experimental data used for comparison showed that bubble nucleation at the wall disrupts the boundary layer structure in the same way as wall roughness. We demonstrate that redefining wall friction by linking the roughness length to the bubble departure diameter produces unexpectedly good results. Only when this new model is activated can the boundary layer be correctly recovered. In addition, this work reveals that the lift force should be activated based on fundamental operating conditions such as system pressure, power, mass flux and subcooling, rather than on bubble diameter alone. The aim of this work is not to introduce a universal boiling model, but rather to highlight a few research directions that may provide greater insight into the fundamental mechanisms governing highly convective boiling flows, including the validity of lift forces in this context.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105609"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relative contributions of drag and non-drag forces governing particle motion in pressurized gas-solid jets","authors":"Donald E. Peterson,&nbsp;Bradley R. Adams","doi":"10.1016/j.ijmultiphaseflow.2026.105612","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105612","url":null,"abstract":"<div><div>This study numerically evaluated the relative contributions of drag (<em>F_D</em>), fluid stress (<em>F_SF</em>), added mass (<em>F_AM</em>), and Basset history (<em>F_H</em>) forces on particle motion as a function of particle size and gas pressure in a one-dimensional gas-solid jet. The analysis used particle and CO₂ gas properties representative of a pilot-scale pressurized oxy-coal combustor inlet at 300 K. Particle diameters of 20-125 μm and gas pressures of 5-40 bar were considered with an inlet velocity of 5 m/s. Force contributions were assessed through force-to-gravity ratios and cumulative force fractions. Results showed that drag was the dominant force beyond the velocity core. However, for larger particles at elevated pressures, <em>F_SF</em> and <em>F_H</em> locally exceeded <em>F_D</em> in regions where gas-particle velocity differences were small. <em>F_SF</em> and <em>F_AM</em> peaked at the gas velocity gradient discontinuity at the jet core exit, while <em>F_H</em> peak lagged this location due to its history effects. <em>F_SF</em> and <em>F_H</em> were consistently greater than <em>F_AM</em> at all conditions. Cumulative force contribution results confirmed that non-drag forces influenced early particle motion for 125 μm particles at 20–40 bar, though their relative importance diminished with distance. Particle velocity responsiveness to changing gas velocity increased with both size and pressure, with non-drag forces most relevant when drag was weak. Findings demonstrate that under high-pressure conditions, forces often considered negligible in atmospheric gas-solid flows may contribute significantly to local particle dynamics.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105612"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large eddy simulation of fiber flocculation in a diffuser: Effects of fiber inertia and reinjection kinematics","authors":"MohammadJavad Norouzi ,&nbsp;Jelena Andrić ,&nbsp;Anton Vernet ,&nbsp;Jordi Pallares ,&nbsp;Håkan Nilsson","doi":"10.1016/j.ijmultiphaseflow.2026.105627","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105627","url":null,"abstract":"<div><div>This study investigates flocculation in dilute suspensions of rigid fibers flowing through an asymmetric diffuser using an Eulerian–Lagrangian approach. The analysis focuses on flow-induced ballistic flocculation under varying fiber inertia and inlet (reinjection) kinematics. The fiber length exceeds the Kolmogorov length scale of the carrier flow, and finite inertia leads to a non-negligible slip velocity relative to the fluid. Large eddy simulation (LES) is applied with a dynamic subgrid-scale model to resolve the flow field and turbulence. One-way coupling between the fibers and the flow is assumed, while fiber–fiber interactions are modeled using short-range attractive forces that promote floc formation. The results show that ballistic deflection significantly accelerates flocculation in the diffuser region, establishing ballistic deflection as the dominant mechanism. In addition, inlet fiber kinematics and inertia strongly influence flocculation within the straight inflow channel.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105627"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation of secondary atomization in high-speed gas flow","authors":"Dajun Xin ,&nbsp;Jinhong Liu ,&nbsp;Kun Xue","doi":"10.1016/j.ijmultiphaseflow.2026.105611","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105611","url":null,"abstract":"<div><div>This study develops empirical correlations for the secondary atomization dynamics of water droplets exposed to high-speed flows spanning three orders of Weber number magnitude (<em>We</em> ∼ O(10¹)–O(10³)). It achieves this by employing shock-tube experiments coupled with time-resolved shadowgraph imaging. Over 100 trials resolve the deformation and breakup processes across subsonic to supersonic regimes. Thereby, the cross-stream deformation rates, maximum flattening ratios, and dimensionless breakup initiation times (<em>τ</em>_b,i) were quantified as functions of <em>We</em>. The results reveal that a two-stage trend in <em>τ</em>_b,i emerges: a rapid decay below <em>We</em> ∼ 500 transitions to a gradual saturation above <em>We</em> ∼ 1500. This is consistent with a shift in breakup regime dominance from bag-type breakup to shear-induced entrainment. A novel grayscale intensity analysis method isolates the core droplet morphology from the surrounding satellite mist. This enables a precise tracking of the transient mass shedding. Core flattening persists until perimeter shear stripping initiates an exponential mass decay that follows a <em>We</em>-independent scaling law in the shear/ Catastrophic regime. Spatial satellite distributions (resolved via high-resolution digital in-line holography (DIH)) reveal <em>We</em>-dependent shedding mechanisms governed by the transition from bag-type (<em>We</em> ∼ O(10¹))to transition from bag-type to shear-driven (<em>We</em> ∼ O(10²)) and shear-driven breakup (<em>We</em> ∼ O(10³)). The transient drag coefficient for the core droplet depends on its aspect ratio, which evolves dynamically with shape deformation and mass shedding. Integrating these correlations for secondary atomization and time-varying drag yields trajectory predictions for core droplet that exhibit deviations less than 7% from experimental data across the tested conditions. This demonstrates the enhanced predictive accuracy of the proposed models over a broad <em>We</em> range.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105611"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of hydrodynamic forces on a finite particle attached to a wall in a confined Couette flow","authors":"Kun Meng ,&nbsp;Binbin Shan ,&nbsp;Yan Cui ,&nbsp;Peng Gao ,&nbsp;Chengjun Zhang ,&nbsp;Xuyao Mao ,&nbsp;Jure Ravnik ,&nbsp;Matjaž Hriberšek ,&nbsp;Yinshui Liu","doi":"10.1016/j.ijmultiphaseflow.2026.105629","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105629","url":null,"abstract":"<div><div>Contaminant particles adhering to walls within narrow fluid clearances significantly degrade the performance and service life of precision systems such as hydraulic components and microsensors. This study investigates the effects of wall confinement on hydrodynamics and particle detachment in a Couette flow, where a spherical particle is attached to the bottom wall and subject to the influence of the top wall. Results demonstrate that confinement deflects streamlines downward and shifts stagnation points upward, thereby reducing flow velocity beneath the particle while accelerating it above. The enhanced particle blockage effect increases both the drag and torque coefficients, while the suppression of vertical velocity markedly reduces the lift coefficient. Phase diagrams identify the critical particle Reynolds numbers for three initial detachment modes (rolling, sliding, and lifting), revealing that rolling detachment is the most readily initiated. Empirical correlations for the force and torque coefficients in confined Couette flow are proposed, along with an algorithm for determining the critical particle Reynolds numbers. These tools can be integrated into Eulerian–Lagrangian computational frameworks to improve the efficiency and accuracy of predicting contaminant particle detachment in precision fluid systems.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105629"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The broken link between space and time in elastic turbulence","authors":"Giulio Foggi Rota ,&nbsp;Rahul K. Singh ,&nbsp;Alessandro Chiarini ,&nbsp;Christian Amor ,&nbsp;Giovanni Soligo ,&nbsp;Dhrubaditya Mitra ,&nbsp;Marco Edoardo Rosti","doi":"10.1016/j.ijmultiphaseflow.2026.105630","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105630","url":null,"abstract":"<div><div>Elastic turbulence (ET), observed in flows of sufficiently elastic polymer solution at small inertia, is characterized by chaotic motions and power-law scaling of energy spectrum (<span><math><mi>E</mi></math></span>) in both wavenumber (<span><math><mi>k</mi></math></span>) and frequency (<span><math><mi>ω</mi></math></span>): <span><math><mrow><mi>E</mi><mrow><mo>(</mo><mi>k</mi><mo>)</mo></mrow><mo>∼</mo><msup><mrow><mi>k</mi></mrow><mrow><mo>−</mo><mi>α</mi></mrow></msup></mrow></math></span> and <span><math><mrow><mi>E</mi><mrow><mo>(</mo><mi>ω</mi><mo>)</mo></mrow><mo>∼</mo><msup><mrow><mi>ω</mi></mrow><mrow><mo>−</mo><mi>β</mi></mrow></msup></mrow></math></span>. Experiments of ET have obtained a vast range of values for the exponent <span><math><mi>β</mi></math></span>. In inertial turbulence, Taylor’s frozen-flow hypothesis implies <span><math><mrow><mi>α</mi><mo>=</mo><mi>β</mi></mrow></math></span>, i.e., spatial and temporal scales are linearly related to each other. In contrast, from high-resolution simulation in three different setups, a tri-periodic box, a channel, and a planar jet, we show that in ET <span><math><mrow><mi>α</mi><mo>≈</mo><mn>4</mn></mrow></math></span> while <span><math><mi>β</mi></math></span> varies significantly. Our analysis shows that in general Taylor’s hypothesis does not hold in ET as there is no universal relation, linear or otherwise, between space and time. We thus clear the confusion of the different scaling exponents found in ET, and focus the attention of future research on understanding <span><math><mi>α</mi></math></span>. Our analysis also implies that waves-like dynamics with a linear dispersion relation (e.g., Alfvén waves) cannot play a role in determining the scaling behavior of ET. The techniques introduced here can be useful for studying smooth chaotic flows in general, e.g., active turbulence.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105630"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adaptively reconstructed spectral eddy-viscosity in large eddy simulations of particle-laden isotropic turbulence, Part I: Particle statistics at low Reynolds number","authors":"Michał Rajek ,&nbsp;Jacek Pozorski","doi":"10.1016/j.ijmultiphaseflow.2025.105584","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105584","url":null,"abstract":"<div><div>Large eddy simulations (LES) of isotropic turbulence coupled with the Lagrangian particle tracking have consistently been disregarded as a means of exploring the physics underlying turbulent dispersed two-phase flows, specifically at Reynolds numbers beyond the reach of direct numerical simulations (DNS). In the current two-part study we focus on evaluating the impact of our recently developed adaptively reconstructed spectral eddy-viscosity on the dynamics of inertial particles in LES of isotropic turbulence. To confirm the robustness of our computational framework, in the present work we first concentrate on the settling speed enhancement, clustering, and relative velocities at low Reynolds numbers. These particle statistics are of importance to determining the collision rates, influencing various environmental phenomena and industrial processes. We also indicate that the LES enriched with a well-established spectral eddy-viscosity which assumes the existence of an infinite <span><math><msup><mrow><mi>k</mi></mrow><mrow><mo>−</mo><mn>5</mn><mo>/</mo><mn>3</mn></mrow></msup></math></span> energy spectrum is unable to reliably predict the radial distribution function and the radial relative velocities at contact. We show that the adaptively reconstructed eddy-viscosity significantly improves the predictive capabilities of LES, thus providing a tool to explore the physics underlying dispersed two-phase flows. We particularly demonstrate that under conditions relevant to cloud turbulence, certain phenomena related to particle motion can be accurately predicted without the subgrid-scale contribution to the fluid velocity at the particle location. In the companion paper we assess the ability of the proposed LES to accurately quantify particle clustering at length scales relevant to the inertial subrange at high Reynolds numbers.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105584"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}