International Journal of Multiphase Flow最新文献

{"title":"Extension of stochastic collision for excentric bubbles in slurry bubble columns","authors":"Christian Walther,&nbsp;Martin Sommerfeld","doi":"10.1016/j.ijmultiphaseflow.2025.105467","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105467","url":null,"abstract":"<div><div>Accurate modeling of bubble-particle interactions is vital for understanding slurry bubble column reactors used in chemical, pharmaceutical, and energy applications. This work introduces a novel extension of a stochastic collision model that accounts for bubble eccentricity and oscillating motion. By applying a hybrid Euler-Lagrange approach with LES turbulence modeling, we demonstrate significant improvements in predicting collision frequencies and solid phase distribution. The model was validated using experimental data from literature and showed enhanced prediction capabilities, particularly for systems with varying particle densities. The results underline the importance of including bubble shape dynamics in three-phase flow simulations.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105467"},"PeriodicalIF":3.8,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262805","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":"Insights into sub-Kolmogorov-scale droplet breakup via boundary element simulations","authors":"Nicholas Morse","doi":"10.1016/j.ijmultiphaseflow.2025.105460","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105460","url":null,"abstract":"<div><div>The statistics of sub-Kolmogorov-scale droplet breakup are investigated at a higher Taylor Reynolds number (<span><math><mrow><mi>R</mi><msub><mrow><mi>e</mi></mrow><mrow><msub><mrow><mi>λ</mi></mrow><mrow><mi>T</mi></mrow></msub></mrow></msub></mrow></math></span>) than similar work at low <span><math><mrow><mi>R</mi><msub><mrow><mi>e</mi></mrow><mrow><msub><mrow><mi>λ</mi></mrow><mrow><mi>T</mi></mrow></msub></mrow></msub></mrow></math></span> (Cristini et al., 2003) to elucidate intermittency and neck pinch off behaviors. To this end, a boundary element method (BEM) is developed to enable simulations of the stochastic Stokes flow about ensembles of droplets along individual trajectories in homogeneous and isotropic turbulence (HIT), made possible through adaptive mesh refinement and fast multipole acceleration. Droplet deformation statistics, near-breakup behavior, and neck thinning statistics at <span><math><mrow><mi>R</mi><msub><mrow><mi>e</mi></mrow><mrow><msub><mrow><mi>λ</mi></mrow><mrow><mi>T</mi></mrow></msub></mrow></msub><mo>≃</mo><mn>310</mn></mrow></math></span> are presented. Results highlight the effect of the HIT’s strain rate intermittency on the droplet deformation statistics, and investigations of subcritical and critical neck thinning events provide insights into the critical disturbances leading to breakup and transition of the neck contraction to the established viscous pinch-off regime. Both the marked influence of intermittency on the droplet deformation statistics and local strain rate effects very close into the terminal pinch-off regime emphasize the multiscale nature of the problem, even for droplets in the idealized Stokes regime.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105460"},"PeriodicalIF":3.8,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217302","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":"Numerical simulation of bedform evolution on granular sediment beds via Eulerian–Lagrangian approach in low-flow-rate horizontal duct transport","authors":"Yang Liu ,&nbsp;Xintao Hu ,&nbsp;Yihe Chen ,&nbsp;Ruixi Cheng ,&nbsp;Weiguo Liang ,&nbsp;Feng Gao ,&nbsp;Yingying Wang","doi":"10.1016/j.ijmultiphaseflow.2025.105463","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105463","url":null,"abstract":"<div><div>Using an Eulerian–Lagrangian approach, we numerically investigate sediment pattern formation during low-flow-rate transport of granular particles in a horizontal duct. Particles introduced at the inlet sediment to form a rising bed near the entrance, which transitions into a horizontal section further downstream. Incipient ripples emerge progressively based on the inclined bed near the inlet, then successively collapse, ultimately giving way to a larger bedform that develops downstream of the ripple sequences. This larger bedform propagates independently downstream over the underlying horizontal bed section. Increasing the flow rate, duct’s height or width, or introducing downward duct inclination promotes bed flattening along the entire duct length. This reduces the distinction between ripples and bedforms, favoring more uniform bed patterns. Our observations reveal three different types of ripple interaction during the coarsening process from ripple array to bedform: splitting, fusion, and the formation of a small sandbag downstream of the parent ripple. We quantify pattern characteristics, including period, wavelength, migration velocity, and particle transport rate as functions of the Shields number. Notably, particle transport rates — whether derived from individual patterns or from creeping of the ripple array — consistently follow the power-law relationship established by Meyer-Peter and Müller. Furthermore, we analyze the morphology of the bed profile in the inclined section near the entrance of the conduct based on the skin friction of the bed surface, as well as the distributions of boundary shear stress along the interface of an individual bedform. For the bedforms with the downstream bed higher than the upstream, the surface shear stress profiles along the bedforms show a distinct downward-pointing cusp near the trough. This feature is analogous to the stress pattern observed upstream of a bump.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105463"},"PeriodicalIF":3.8,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145216864","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 unsteady behavior of a freely closed ventilated supercavity at low Froude numbers","authors":"Wanning Li ,&nbsp;Huacheng Mei ,&nbsp;Cong Wang ,&nbsp;Jiangcheng Que","doi":"10.1016/j.ijmultiphaseflow.2025.105464","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105464","url":null,"abstract":"<div><div>An experimental study was conducted to examine the unsteady flow characteristics of a freely closed ventilated supercavity induced by a disk-shaped cavitator. Within the explored parameter range, four distinct cavity closure modes were identified: Foam Cavity (FC), Twin Vortex (TV), hybrid Foam Cavity and Re-entrant Jet (FCRJ), and hybrid Twin Vortex and Re-entrant Jet (TVRJ). Among these, the Twin Vortex mode was most commonly observed at low Froude numbers, characterized by periodic shedding of small bubbles and the presence of a pair of vortex tubes connected to the cavity tail, exhibiting regular breakup events and fluctuations in both diameter and axial position. High-precision dynamic pressure sensors was employed to investigate spectral features of internal cavity pressure and surrounding ambient pressure across various closure modes and flow conditions. Results revealed that, in the low-frequency range 0∼50Hz, incoming flow disturbances predominantly influenced cavity pulsations, whereas cavity oscillations themselves also significantly affected pressure fluctuations in the external flow field. In the intermediate-frequency range 50∼300Hz, distinct energy peaks emerged, attributable to intrinsic unsteady flow structures within the supercavity. Moreover, at high-frequency range 300∼3000Hz, evenly spaced spectral peaks were observed, corresponding to the excitation of standing wave modes within the slender supercavity body.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105464"},"PeriodicalIF":3.8,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155298","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":"Bubble dynamics near a rigid boundary with a protruded cone","authors":"Wen-Tao Wu,&nbsp;Jun-Jie Zhou,&nbsp;Da-Hao Xie,&nbsp;Shi-Ping Wang","doi":"10.1016/j.ijmultiphaseflow.2025.105456","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105456","url":null,"abstract":"<div><div>This study investigates bubble dynamics near a rigid boundary consisting of a protruded cone and a plane. This boundary represents irregularly shaped structures or protruding components, often occurring in practical applications. This phenomenon, under an axisymmetric configuration, is investigated through numerical simulations based on the compressible Navier–Stokes equations and the Volume of Fluid (VOF) method, which has been validated for accurately capturing bubble dynamics. Both bubble dynamics and bubble-jet formation are analyzed parameterized by the cone apex angle (<span><math><mi>β</mi></math></span>) and dimensionless distance (<span><math><mi>γ</mi></math></span>) of the bubble center from the cone vertex. We identify four distinct jet regimes: thin needle jets, annular jets, boundary-attached regular jets, and boundary-divergent regular jets. Furthermore, the pressure for two regular jet configurations at the boundary demonstrates strong agreement with theoretical models. Notably, an extreme case marked by complete jet suppression is observed.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105456"},"PeriodicalIF":3.8,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145216863","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 continuum thermodynamic model of the influence of non-ionic surfactant on mass transfer from gas bubbles","authors":"Dieter Bothe ,&nbsp;Akio Tomiyama","doi":"10.1016/j.ijmultiphaseflow.2025.105453","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105453","url":null,"abstract":"<div><div>Mass transfer of gaseous components from rising bubbles to the ambient liquid depends not only on the chemical potential difference of the transfer component but also on the interfacial free energy and composition. The latter is strongly affected by surface active agents that are present in many applications. Surfactants lead to local changes in the interfacial tension, which influence the mass transfer rates in two different ways. On the one hand, inhomogeneous interfacial tension leads to Marangoni stress, which can strongly change the local hydrodynamics, thus impacting the local mass transfer. On the other hand, the coverage by surfactant molecules results in a mass transfer resistance. This hindrance effect is not included in current continuum physical models. The present work provides the experimental validation of a recently introduced extended sharp-interface model for two-phase flows with mass transfer that also accounts for the mass transfer hindrance due to adsorbed surfactant. The crucial feature is to account for area-specific concentrations not only of adsorbed constituents but also of transfer species, and to model mass transfer as a series of two bi-directional sorption-type bulk-interface exchange processes. The resulting model is shown to quantitatively describe experimental measurements on mass transfer reduction for the dissolution of CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> bubbles in different surfactant solutions.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105453"},"PeriodicalIF":3.8,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217301","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":"Experiments and modeling of pressure drop for the droplet flow system in a tubular packed bed","authors":"Jinjin Cai ,&nbsp;Xueke Dong ,&nbsp;Zhengnan Sun ,&nbsp;Xinjie Huo ,&nbsp;Tonghuan Yu ,&nbsp;Yang Luan ,&nbsp;Feng Zhou ,&nbsp;Zhenyu Wu ,&nbsp;Yong Nie","doi":"10.1016/j.ijmultiphaseflow.2025.105462","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105462","url":null,"abstract":"<div><div>In droplet flow systems, pressure drop is a critical parameter reflecting energy dissipation, which directly impacts the droplet dynamics and consequently guides the equipment design and optimization. Most modeling studies on droplet flow pressure drop primarily focus on the frictional pressure drop under the homogeneous fluid flow assumption. The contribution of interfacial drag to the pressure drop is overlooked, which leads to a lack of deeper mechanistic understanding of pressure drop and the limited predictive accuracy of current models. In this work, the droplet flow experiments in a tubular packed bed were performed to systematically quantify the interfacial drag. The coupling of interfacial drag with droplet size was characterized and a pressure drop model integrating both frictional and interfacial contributions was developed. First, the variation in droplet size was captured using a microphotography technique. Subsequently, the pressure drop was measured with varying flow velocity, dispersed phase holdup, and packed bed diameter. The contribution of interfacial drag to pressure drop was discussed by analyzing droplet dynamics. Finally, the correlation between interfacial drag and droplet size was established. A model combining the frictional and interfacial pressure drop was proposed, achieving a mean relative error of 2.08%. Furthermore, validation experiments confirmed that the developed model precisely captures the contribution of interfacial drag mechanisms and substantially enhances the accuracy of pressure drop prediction in droplet flow systems.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105462"},"PeriodicalIF":3.8,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155295","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":"Exner diagnosis method for two-fluid morphodynamics simulations","authors":"Alban Gilletta ,&nbsp;Cyrille Bonamy ,&nbsp;Julien Chauchat","doi":"10.1016/j.ijmultiphaseflow.2025.105457","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105457","url":null,"abstract":"<div><div>Mass balance in sediment transport is often associated with single-phase flow model through the resolution of the Exner equation. In this contribution, the mass balance is derived from the two-phase flow, two-fluid, model equations and compared with the conventional single-phase flow approach. Five terms are identified from the two-phase flow formulation: the bed evolution, the storage evolution, the lateral flux, the bed flux and the top flux. Three different flow configurations with increasing complexity are tested, namely a one dimensional pure sedimentation, a two dimensional scour downstream an apron and a three dimensional scour around a vertical square cylinder. The mass balance formulation identifies the driving process of an erosion or a deposition process in each case. This approach can be applied on other configurations related with sediment flux and morphology bed evolution such as scour process.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105457"},"PeriodicalIF":3.8,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155297","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":"Numerical investigation on atomization of multiple jets impinging at an annular liquid film with elevated gas-to-liquid density ratio","authors":"Yuan Li ,&nbsp;Jiawei Jiang ,&nbsp;Hang Fu ,&nbsp;Yuyuan Zhang ,&nbsp;Anlong Yang ,&nbsp;Chenglong Tang","doi":"10.1016/j.ijmultiphaseflow.2025.105450","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105450","url":null,"abstract":"<div><div>Bi-propellant atomization of pintle injector is modeled as multiple jets (oxidizer) impinging an annular liquid sheet (fuel). Numerical simulation of the atomization behaviors is conducted at elevated gas to fuel density ratios with coupling Eulerian–Lagrangian approach. A dual-loop tagging algorithm is proposed to identify the droplets without additional mesh refinement. Our results show that for all density ratio cases investigated here, the atomization field can be characterized by three regions quantified by mass fraction (mixing, transition and falling region). These regions have significantly different droplet size and mixing ratio distributions. SMD decreases in the mixing region, but in the transition and falling region, SMD firstly increases and then decreases. Furthermore, at low density ratio, the mixing ratio presents the unimodal variation trend, while at high density ratio, the mixing ratio presents the bimodal mode. To interpret the effect of the density ratio on the above observations, the continuous mixing sheet and the falling sheet breakup, as well as the discrete droplet coalescence mechanism is analyzed and it is found that higher density ratio leads to advanced breakup of liquid sheets in both mixing and falling regions, which generates more discrete ligaments or droplets in the transition region. However, on the other hand, at sufficiently high density ratio, the discrete ligaments and droplets are so populated that their coalescence mechanism is speculated to be effective, leading to larger sized discrete liquid structures and bimodal variation of mixing ratio.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105450"},"PeriodicalIF":3.8,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145118384","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":"Interface coupling effects on Rayleigh–Taylor and Faraday instabilities in granular suspensions under oscillatory forcing","authors":"Senlin Zhu ,&nbsp;Qingfei Fu ,&nbsp;Lijun Yang","doi":"10.1016/j.ijmultiphaseflow.2025.105448","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105448","url":null,"abstract":"<div><div>This study investigates how interface coupling effect affects the sedimentation dynamics of finite-thickness granular suspensions under both constant gravity and oscillatory accelerations. Through Euler–Lagrange simulations, we examine the evolution of Rayleigh–Taylor instability (RTI) at the lower interface. Under constant gravity, reducing suspension thickness, thereby intensifying interface coupling effects, suppresses the growth rate of RTI while increasing the dominant wavenumber. Under oscillatory acceleration, two competing mechanisms emerge: while reduced thickness inherently inhibits RTI growth in the absence of oscillation, it simultaneously weakens oscillations’ stabilizing effect. This competition leads to a reversal of behavior observed under constant gravity, wherein high-amplitude oscillations cause thinner suspensions to exhibit more rapid instability growth than thicker layers. Linear stability analysis captures this reversal and matches numerical results well. It further demonstrates that, due to the attenuated effect of oscillation-induced stabilization, increasing oscillation amplitude inevitably induces growth rate inversions from high to low wavenumbers in thinner suspensions; nevertheless, these suspensions consistently maintain higher dominant wavenumbers. Additionally, granular suspensions can also develop Faraday instability (FI) at the upper interface, with its dominant wavenumbers increasing with oscillation frequency, though this increase diminishes particle resolution at interfaces, leading to reduced consistency between theoretical and numerical results.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"194 ","pages":"Article 105448"},"PeriodicalIF":3.8,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145118386","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}